so i play singleplayer 1.12.2 and when i close the game and reopen the chunkloader in the nether stops working and the little ball that spins doesnt spin and just sits ontop the chunkloader.

You have the chunk loader next to an active lever, it is redstone controlable.

ah i see didnt know that although could have sworn i had it farther than 2 blocks away from the lever the first time. but i moved it and it doesnt seem to stop working anymore. sorry for the inconvenience