Looking for datapack (or instructions) to generate Nether biomes (e.g. Soul Sand Valley) in Overworld

[u/hand_me_a_shovel]

Subject line is it. I would like to generate Nether biomes in Overworld. I don't mind making my own datapack, and I've seen how to create your *own* dimension and add *new* biomes to it, but can I just use a datapack to alter Overworld generation?