Nosediving could be either be caused by the nock being set too high or the tiller being adjusted wrong. Fortunately, both are adjustable on the Dalaa.
With most of my bows, I find that a nock height of about 1/2" works best, but with the Dalaa 3/8" works better.
The manual explains how to adjust the tiller. Or, if you call the factory, I'm sure they will give you some pointers as to which way to adjust it to eliminate the nosediving. If it were me, I would start with one revolution of the tiller adjusting screw in opposite directions on the top and bottom limbs. If that makes things better, fine, if worse, then try a revolution in the other direction.
Nock high can also be caused by form problems, if you're pressing down on the nock with your forefinger, causing a bow in the arrow that rebounds off the shelf.