Where to Find and Catch Quilladin
From Pokemon Go Wiki
Quilladin are found and captured in Nest and Habitat locations.
Nests
Quilladin Nests are locations that consistently spawn Quilladin.
Habitats
Quilladin Habitats are spawn locations where Quilladin 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: