"just"... Nuclear matter is very stiff. It can make a mass of the order of the Sun's, falling down with a significant fraction of the speed of light, bounce wi

"just"... Nuclear matter is very stiff. It can make a mass of the order of the Sun's, falling down with a significant fraction of the speed of light, bounce without becoming a black hole. So the pressure you'd need to make a black hole with higher-than-nuclear density would be, well, astronomical.