Generating a world with the same seed with or without Nomadic Tents does create the same world generation. More precisely, some parts of the world will be similar, others won't.

Reproduction

To reproduce the bug, I will give you example seed and coordinates:
Seed: 1241
At (440, 640) the world generation is the same. But if you walk 100 blocks west, a taiga biome that is present without NT is replaced by a plains biome with the mod.

Note that I have other mods installed, but this issue appears only if I add Nomadic Tents.

More information:

Forge Version: 1.12.2-forge1.12.2-14.23.5.2847
Mod Version: 9.5.2
Mods installed:
AdventOfAscension 3.2.1
Backpack 3.2.0
Chest Transporter 2.8.8
Damage Indicators
Davincis Vessels 6.340-full
GraveStone
IronChests
IvyToolkit 1.3.3
JEI 4.15.0.269
movingworld 6.342
Optifine 1.12.2_HD_U_E3
SmoothBedrock
XaerosMinimap 20.0.0

I hope I don't forget anything

1.12 is no longer supported. Sorry for any inconvenience.

This is strange, but I don't think there's anything I can do about it. I can't find anywhere in my code where I'm using the Overworld random number generator, which is the only reason I could imagine causing this problem.

Generating a world with the same seed with or without Nomadic Tents does create the same world generation. More precisely, some parts of the world will be similar, others won't.

Reproduction

To reproduce the bug, I will give you example seed and coordinates:
Seed: 1241
At (440, 640) the world generation is the same. But if you walk 100 blocks west, a taiga biome that is present without NT is replaced by a plains biome with the mod.

Note that I have other mods installed, but this issue appears only if I add Nomadic Tents.

More information:

Forge Version: 1.12.2-forge1.12.2-14.23.5.2847
Mod Version: 9.5.2
Mods installed:
AdventOfAscension 3.2.1
Backpack 3.2.0
Chest Transporter 2.8.8
Damage Indicators
Davincis Vessels 6.340-full
GraveStone
IronChests
IvyToolkit 1.3.3
JEI 4.15.0.269
movingworld 6.342
Optifine 1.12.2_HD_U_E3
SmoothBedrock
XaerosMinimap 20.0.0

I hope I don't forget anything

This is strange, but I don't think there's anything I can do about it. I can't find anywhere in my code where I'm using the Overworld random number generator, which is the only reason I could imagine causing this problem.

I tried to reproduce the Bug using the same setup but i was unable to include Backpacks 3.2.0 because i did not know with Backpack mod was used.

I used the same seed as described above with the "Default" World Gen type.

Test #1: W/O Nomadic Tents, TP'd to (440.640) and found Plains Biome. Moved 100 blocks West (340,640) and still same biome. Moved 100 blocks East (540,640) still same biome. Exited game.

Test #2: With Nomadic Tents and same map. Entered game at (340,640) Still Plains Biome and at the other locations (440,640) & (540,640).

I generated a New Map with Seed: 1241 and World Gen Type: Large Biome.

Test #3 : W/O Nomadic Tents, TP'd to (440.640) and found Taiga Biome. Moved 100 blocks West (340,640) and still same biome. Moved 100 blocks East (540,640) still same biome. Exited Game.

Test #4: With Nomadic Tents and same map. Entered game at (340,640) Still Taiga Biome and at the other locations (440,640) & (540,640).

@matthiasrsl If, i could get the name (Correct Name) for the Backpack 3.2.0 Mod i will create new maps to test with said Mod.

@skyjay1 I will run more tests and let you know here when i get the correct Backpack 3.2.0 Mod installed.