CD and Geno said that they fouled Diggins 3 times down the court (with a foul to give) but they weren't called.
I watched the replay off the last 15 seconds about 20 times. There was no clear foul on Diggins. Perhaps, right at the end, when the defender dove at the ball and fell down, but even that was marginal. If they intended to foul, then they should have fouled clearly. It seemed as if they did not intend to foul.
Although the play did not work, the real issue I saw was that Dolson and ML did not run back on D, and then the defender on Diggins dove for the dribble steal and another defender took herself out of the play going behind Diggins rather than getting between the ball and basket and picking up a ND player.
ML started from out of bounds, so it's understandable that she didn't get back.
But Dolson didn't move until all the ND players had blown by her. Not good at all considering it was a tie game with 9 seconds to play.