Whether or not it nosedives would depend on how accurately the problematic MCAS systems (which then actuate the flight surfaces) are simulated.
With working MCAS, it should fly roughly like the pre-MAX version, with automatic trim adjustments to hide the significant pitch up tendency that the pre-MAX version with its much smaller engines did not have.
With a buggy MCAS with the failure conditions met, you might have sporadic significant pitch-down.
(... And with a blown load reduction device in the left engine, e.g. from a large bird strike, you'll have the cockpit filled with smoke at fatal toxicity within 39 seconds, but despite being completely avoidable by flicking one switch, and despite also affecting other aircraft with similar devices, the FAA doesn't find it worth any immediate action.)
Almost all flights other than by test pilots or air show pilots will never have MCAS do anything unless it receives faulty sensor data, as was the case in the two crashes.
Boeing used to be a great company that prioritized safety over everything else. (If it ain't Boeing, I ain't going) The "merger" with McDonnell Douglas was the end of that version of Boeing. IMHO, the Boeing 777 was the last great airplane Boeing built. That plane would not be made in the Boeing of today because the initial investment was so high.