If it is truely "major nose heavy" that's as bad or worse than tail heavy. A very nose heavy aircraft will stall/snap/spin in a heartbeat, particularly when using lots of elevator out of a dive. Tied to very large elevator throw it's no wonder the airplane is scaring you. A nose heavy aircraft situation works the wing the hardest because it has to generate more angle of attack to fly the airplane, leaving little left over for maneuvers.

A tail heavy airplane works the wing the easiest but it also causes pitch up's which lead to stalls and maybe spins. An aft Cg is the usual cause of a true flat spin (rotating in yaw with fuselage parallel to the ground). Power (with recovery controls) is the only thing that will get you out of a flat spin.

Recommendation: remeasure the Cg and get it to 25-30% of the MAC.