The Buffaloes made only one 3-pointer in regulation before hitting both of their attempts in overtime.
Tech, trailing 72-69, had a chance to tie it with time running out, but Natalie Ritchie's 3-point attempt was blocked by Britt Hartshorn. Nightingale then sank two free throws with 10.4 seconds left to seal the victory.
Tera Bjorklund led the Buffaloes (17-6, 7-3 Big 12) with 18 points. Roulier added 16, and Nightingale 15.
Tech (13-7, 5-5) got 22 points and 16 rebounds from Jolee Ayers. Casey Jackson and Jia Perkins scored 12 points each, and Amber Tarr added 11.