The biomes, crimson forest, warped forest, and soul sand valley are not generating properly in the nether. For example no trees will spawn in the two forest biomes and no soul sand generates in soul sand valley, they just look like normal nether wastes. They still spawn a few features, the soul sand valley will still generate bone structures, and the two forests will still generate some of the respective vines generating on the floor or ceiling. All the biomes still spawn the correct mobs: skeletons, hoglins and endermen respectively.

From what I can tell Basalt Deltas generate correctly