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