Earlier quoted context omitted.
Nvidia would also use TSMC 7nm since it is much better that Samsung 8mn. So potentially they are also waiting for the TSMC availability.
How is it 'much better'? 7nm is not better than 8nm because it has a smaller number - the number doesn't correlate strongly with transistor density these days.
But Nvidia has Ampere on both TSMC 7nm (GA100) and Samsung's 8nm (GA102). The TSMC variant has a significantly higher density at 65.6M / mm² vs. 45.1M / mm². Comparing across architectures is murkey, but we also know that the TSMC 7nm 6900XT clocks a lot higher than the Samsung 8nm RTX 3080/3090 while also drawing less power. There's of course a lot more to clock speeds & power draw in an actual product than the raw fab transistor performance, but it's still a data point.
So there's both density & performance evidence to suggest TSMC's 7nm is meaningfully better than Samsung's 8nm.
Even going off of marketing names, Samsung has a 7nm as well and they don't pretend their 8nm is just one-worse than the 7nm. The 8nm is an evolution of the 10nm node while the 7nm is itself a new node. According to Samsung's marketing flowcharts, anyway. And analysis suggests Samsung's 7nm is competitive with TSMC's 7nm.