I disabled all mods except BetterWardrobe and these are the lua errors I get when trying to view sets and extras.

Message: Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:6903: attempt to call field '?' (a nil value)
Time: Sun Feb 12 01:54:17 2023
Count: 1
Stack: Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:6903: attempt to call field '?' (a nil value)
[string "@Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua"]:6903: in function <Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:6899>
[string "@Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua"]:6951: in function UpdateSets' [string "@Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua"]:7540: in function ResetPage'
[string "@Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua"]:6891: in function Refresh' [string "@Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua"]:6798: in function <Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:6786> [string "=[C]"]: in function SetShown'
[string "@Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua"]:1299: in function SetTab' [string "@Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua"]:1187: in function ClickTab'
[string "*Wardrobe.xml:450_OnClick"]:1: in function <[string "*Wardrobe.xml:450_OnClick"]:1>

Locals: model = DressUpModel {
RefreshTooltip = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:3225
OnLeave = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:3308
OnShow = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:3313
OnLoad = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:3184
OnHide = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:3317
cameraID = 1027
Border = Texture {
}
OnEvent = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:3198
SetInfo = Frame {
}
CollectionListVisual = Frame {
}
OnModelLoaded = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:3321
TransmogStateTexture = Texture {
}
OnMouseDown = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:3204
OnEnter = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:3219
Favorite = Frame {
}
0 =
}
_ = "Dark Iron Dwarf"
raceFilename = "DarkIronDwarf"
gender = 3
(*temporary) = nil
(*temporary) = "attempt to call field '?' (a nil value)"
addon =

Message: Usage: local apppearances = C_TransmogSets.GetSetPrimaryAppearances(transmogSetID)
Time: Sun Feb 12 01:56:32 2023
Count: 8
Stack: Usage: local apppearances = C_TransmogSets.GetSetPrimaryAppearances(transmogSetID)
[string "=[C]"]: in function GetSetPrimaryAppearances' [string "@Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua"]:3236: in function RefreshTooltip'
[string "@Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua"]:3222: in function <Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:3219>

Locals: (*temporary) = "Usage: local apppearances = C_TransmogSets.GetSetPrimaryAppearances(transmogSetID)"

Message: Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:6903: attempt to call field '?' (a nil value)
Time: Sun Feb 12 01:57:43 2023
Count: 1
Stack: Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:6903: attempt to call field '?' (a nil value)
[string "@Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua"]:6903: in function <Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:6899>
[string "@Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua"]:7056: in function UpdateSets' [string "@Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua"]:7540: in function ResetPage'
[string "@Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua"]:6891: in function Refresh' [string "@Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua"]:6798: in function <Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:6786> [string "=[C]"]: in function SetShown'
[string "@Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua"]:1299: in function SetTab' [string "@Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua"]:1187: in function ClickTab'
[string "*Wardrobe.xml:485_OnClick"]:1: in function <[string "*Wardrobe.xml:485_OnClick"]:1>

Locals: model = DressUpModel {
0 =
OnEnter = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:3219
Border = Texture {
}
OnMouseDown = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:3204
cameraID = 1027
RefreshTooltip = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:3225
TransmogStateTexture = Texture {
}
OnShow = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:3313
OnLoad = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:3184
OnHide = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:3317
OnEvent = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:3198
CollectionListVisual = Frame {
}
OnLeave = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:3308
SetInfo = Frame {
}
Favorite = Frame {
}
OnModelLoaded = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:3321
}
_ = "Dark Iron Dwarf"
raceFilename = "DarkIronDwarf"
gender = 3
(*temporary) = nil
(*temporary) = "attempt to call field '?' (a nil value)"
addon =

Thanks for the fix. I'll get a update out shortly

I went into the changelog, and saw that some lines were updated in the last version, and those updated lines (before the update) is the same that is throwing an error now, so I tried to fix it, and so far it seems to be working.

Open up BetterWardrobe/Modules/Wardrobe.lua, navigate to line 6903 (inside function SetModelUnit), and change the line from

local force = addon.Globals.mods[addon.Profile.TooltipPreview_SwapModifier]()

to

local force = addon.Profile.TooltipPreview_SwapModifier ~= L["None"] and addon.Globals.mods[addon.Profile.TooltipPreview_SwapModifier]()

That seems to fix the issue for me, thank you!

That appears to have worked for me too. Ty so much.