Has an NBA game ever ended 115-90?
It has. 115-90 has been a NBA final 31 times in 73,172 games. The first was Boston Celtics beat St. Louis Hawks on October 22, 1957; the latest was Dallas Mavericks beat Miami Heat on January 20, 2023.
That makes 115-90 the 752nd most common final score out of 3,189 that have ever occurred in NBA. One point away, 116-90 has happened 11 times and 115-91 has happened 25 times.