NVIDIA is not a "real" competitor to Intel or AMD when focusing on production of CPUs for PCs. The most PCs have Intel or AMD processor. NVIDIA is the top producer of GPUs and graphics cards. But this may change in the future, because NVIDIA plans to produce also CPUs for PCs.
NVIDIA is a real competitor to Intel or AMD at the level of semiconductor chip making industry. The company produces a high-performance GPUs for gaming, crypto mining, video editing and for other professional needs. They also sell chips for use in vehicles, robotics and many of their chips are used in supercomputers. NVIDIA is a leader in the production of next-generation AI chips, which are a big source of their revenue. Intel has started to produce AI chips later, so it is not so competitive in AI chips segment.