This is true but people need to understand that whomever has the most powerful navy stays in power it's been true throughout history right now the United States has the most powerful navy counting aircraft carriers and nuclear submarines China and Russia are way behind and the ONLY deterrent is Nukes and mutually assured destruction but if it ever comes to an invading force....China definitely has the numbers.Two nuclear powers will never escalate more than guns and a rocket or two. It can go badly too quickly.
India and Pakistan hate each other and have had border beefs, nothing more than shooting. Both have nukes.
North and South Korea (via US controlled) have nukes and nothing more than tit for tat squirmishes.
Two major nuclear powers like US and China won't get anywhere close to an all out war. Neither can 'win' in the traditional sense.