Whenever I go to the Nether and come back I spawn somewhere random and my chunks break.

From: https://www.reddit.com/r/Minecraft/comments/f499am/i_need_urgent_help_basically_whenever_i_go_to_the/

Player was able to link the portals properly from the comments but was unable to reload chunks.

 

See video attached on Reddit or at https://streamable.com/m6kn8