So I went and did my research and these are the runners-up after Nicki for being the female rappers with the most top 10s on the Billboard hot 100:

Missy Elliot - 12 (notably she is the lead artist on 6, precisely half, of these entries.)
Lil' Kim - 5
Eve - 4
Da Brat - 3
Iggy Azalea - 3
MC Lyte - 3