I have installed MultiverseNetherPortals recently. I have linked my main world to my nether world. I also have a separate world for Building. But whenever I leave the nether it sends me to my flatland world that no one should be in. Can I link the nether to my main world?
Multiverse-NetherPortals is specifically for having an individual nether for each overworld. Unless you need multiple nether worlds, MVNP is of no use to you. Without the plugin, the nether should be linked to your main world anyway! If your end goal is to have a main world, nether, end, and a flatland for creative building, then you only need MV-Core, MV-Inventories, and MV-Portals.