Pokemon nests can be difficult to keep track of. Reddit user u/Zyxwgh has here a rundown of Pokemon nesting habits.
Babies, legendaries and Absol and Mawile don't spawn in the wild and therefore they don't nest;
Babies' first evolutions count as "unevolved adults" that may nest;
Evolved species (except for direct evolutions from babies) don't nest.
List of all NON-NESTING species
- Current or former regional exclusives: Mr. Mime, Tauros, Kangaskhan, Farfetch'd, Heracross, Corsola, Zangoose, Seviper, Relicanth
- Most 10km eggs: Dratini, Larvitar, Porygon, Chansey, Mareep, Sudowoodo, Aerodactyl, Snorlax, Lapras, Miltank, Ralts, Slakoth, Feebas
- Some former 10km eggs (now 5km eggs): Pineco, Gligar
- The Hitmons: Hitmonlee, Hitmonchan, Hitmontop
- The Purple Polluters: Grimer, Koffing
- Three of the many Gen4 evolvables: Lickitung, Tangela, Snorunt
- The weather-elusive (or exclusive?): Lotad
- 4 special cases: Togetic, Ditto, Unown, Delibird