Just general flowering plant feed. In the weather you’re having get em outside in the sun and plenty of water. If it’s a very young plant, be a tad more careful with full sun. But most chilies are pretty tough plants.
I take it outside in the sun often and I'm careful not to overwater, it's doing well after about 4 months and most plants are dead by them with me.
Just don’t let the soil dry out. Especially if it’s in the sun. They like sun on the plant, but keep the roots moist.