What happens to Nuka World's parks if you do Open Season after Power Play?

[Agent Chieftain]

Do the raider's continue to spawn in the parks you assinged to them? Or do they just get cleared out?

[Yhwach]

No, they won't respawn.
NPC's will just kinda sit there, more won't show up, and the Slaves will lose their clothes after awhile.
There's a mod to populate the park with Minutemen on nexusmods:
https://www.nexusmods.com/fallout4/mods/30509

[enhjester]

They don't respawn in the park. But you will find pockets of resistance outside of the park.

[Ez Duzit]

The assigned factions will remain in the parks you assigned to them until you clear them out. After that they WILL occasionally respawn but not very often. But like enhjester said you'll find pockets of them in the surrounding areas. I've found that alot of them spawn at the vacant building behind the Nuka World Red Rocket. Some pretty good battles go down there between raiders and super mutants. Also a few other locations to discover in that area of the map.