Where to Find and Catch Tapu Koko
From Pokemon Go Wiki
Tapu Koko are found and captured in Nest and Habitat locations.
Nests
Tapu Koko Nests are locations that consistently spawn Tapu Koko.
Habitats
Tapu Koko Habitats are spawn locations where Tapu Koko is likely to be encountered, but not guaranteed the way a Nest is.
Additional Tips and Information
Best Nests
If you know a really good nest or any of the nests above is really good, list them here: