Those are wasp. Appears to be Yellow Jackets.
Not good. You might want to contact an exterminator for various reasons... they are aggressive when threatened and the spray is poison.

Depending on how far into the light fixture/home they've migrated, store bought wasp spray might work if you choose to DYI, just be careful and monitor its effectiveness.

Once eradicated, make sure to seal the opening, otherwise they will return. Hope this helps.
https://www.britannica.com/animal/yellow-jacket