My Nucleo-F446RE arrived yesterday. It works fine with the ST Core from ST Microelectronics. Install it via the Boards Manager.
I have just released v2.9.8 of MCUFRIEND_kbv library. Update with the Library Manager.
If you have been using a hacked or Beta version, delete the directory and install new version from scratch.
The F446 is too fast for ILI9320 class of controller. MIPI controllers should be fine. Shout if you have a problem.
David.