I was never able to get the nose down until I got the disc pivot thing down. I'm still not great at it, but I'm working on it. JHern did a really good job of describing what I am talking about:
JHern wrote:I get the nose down going into very last part of the rip...I have no idea if it is down before then, but I do know it is afterward. The motion of opening your wrist and slinging the disc forward around your lock finger on the inside rim creates the opportunity you need to get a flat and level release.
Experiment with the way you apply the final grip pressure just before the rip, and you'll find something that gets that nose down for you.
Basically, if you aren't getting the disc to feel heavy and pivot out of the rip, you aren't really going to be able to manipulate the nose angle. I struggled with it for so long, then I got this SEEMINGLY unrelated aspect of the throw to happen and realized that it's a that moment that you are able to manipulate the nose angle etc.... It's just hard to describe.
Also I think getting your weight forward is a type of OAT that makes the nose go down. Since you are moving forward on a horizontal plane, and throwing at slightly upward trajectory, it kind of pushes the nose down, in relation to the plane you are actually thowing on. Just something I've been thinking about lately.