Has an NBA game ever ended 90-77?
Yes. NBA has seen a final score of 90-77 27 times. It first happened on November 19, 1950, when Minneapolis Lakers beat Rochester Royals, and most recently on January 17, 2013, when Los Angeles Clippers beat Minnesota Timberwolves.
That makes 90-77 the 828th most common final score out of 3,189 that have ever occurred in NBA. One point away, 91-77 has happened 21 times and 90-78 has happened 30 times.