On the nose means the character says exactly what they feel, everybody nods, and the scene dies.

You'll know it by the shape. Someone announces the theme. Someone explains their own damage. Two people agree about what just happened. The information is right and the scene is dead, because there's nothing left for the audience to do. Watching a movie is work. When you do all the work, they stop.

The fix isn't to be vague. Vague is worse. The fix is to give the character something else to want in the scene, so the real thing has to come out sideways. In Michael Clayton, Tony Gilroy has Tilda Swinton rehearse her answers alone in a hotel bathroom before she says them out loud in the meeting. She never tells us she's terrified. You watch her practice being calm, and you know.

Try it on your own pages. Find a line where somebody says what they feel. Then ask what they'd be doing instead if they couldn't say it. Fixing the coffee. Reading the wrong email twice. Correcting a small thing that doesn't matter. Put that in, cut the line, and see if the scene still works. Most of the time it works better, because now the audience has to lean in.

The line to keep is the one the character can't help saying. Everything else is you explaining.