Or at least not NJ, many other cheaper places to live.
But if he does a good job saving his money, cost of living becomes less critical. He can choose where he wants to retire based on factors other than cost of living.
For example, a lot of people from NJ retire in North Carolina. The cost of living in the Charlotte, NC, area is about 22% lower than the cost of living in central NJ. But the bulk of that difference is because of the cost of housing. The OP already owns a house (and presumably the mortgage will be paid off by the time he retires), so the cost of housing is not a critical factor here. Once you take housing out of the equation, the cost of living in the Charlotte area is only about 8% lower than central NJ.
Certainly 8% is a big difference if you are struggling to make ends meet. Plus if you are struggling to make ends meet, you can sell your house in NJ and buy a cheaper house in NC, and then spend the extra cash from the liquidated real estate.
But if the OP has saved enough to live comfortably in retirement, the 8% difference in cost-of-living is probably not something that is going to drive his decision on where to retire.
Likewise when you look at taxes. If the OP and his wife have taxable income in retirement of about $105K, their NC income tax would be about $3000 higher than their NJ income tax. (If their retirement income is $55K, they pay about $2000 more in NC income tax than NJ.) Of course that difference is offset by property taxes which average about $4000 more in NJ than NC. So the total tax burden (income + property) is about $1000 more in NJ if they earn $105K. (It is actually less than that, because the additional tax in NJ is deductible from Federal income tax.)
Again, if they have managed their investments so they have retirement taxable income of $105K they are living comfortably enough that they don't have to worry about the extra $1000 in NJ taxes or the 8% higher cost of living. They can make their decision about where to retire based on other factors like location of family, climate, recreational activities, health care, etc. They may still decide to retire in NC, but it would be a decision based on quality of life, not economic forces.
That is why the consistent advice in this thread is to comfortably live a modest lifestyle and save as much as you can toward retirement. Then in retirement, you can afford to continue to live your lifestyle and you can afford to make your own decisions rather than be forced into them.