FOLLY: La Taverna
NOSA: That's ~5k/head. Take out taxes and you're at ~4k. That's maybe a main and a drink (probably water). You're not going to get "good ambience" at that price point.
FOLLY: The Golden Tulip Hotel in Festac. I can't remember the exact amount but the buffet was about N6000 for brunch and it was pretty good.
NOSA: Orchid Bistro in Ikeja