Chances of successful pregnancy after 2 miscarriages and neonatal death?

Depends. The chances of a successful pregnancy would depend on the reasons for the miscarriages and the neonatal death. Miscarriages are relatively common, but when a women has multiple miscarriages, that can indicate and underlying medical/genetic condition that may make it more difficult to have a normal pregnancy.
Hard to day. This situation calls for an evaluation preferably prior to next pregnancy attempt. Genetics, infections, hormones etc can all be worked up to see where the problem may lie. Good luck.