@Anne9667 Right, it has to be reported in both countries.
But the Mexican tax bureau just changed the laws regarding income property and it's much better for hosts. You can no longer claim deductions for expenses, but instead of all the various taxes they applied to rentals before, it is now just a straight across 4% plus IVA. You can deduct the IVA you paid on expenses with official facturas, but you can't deduct the cost of the expenses themselves.
A Mexican accountant will know all this.
However, because you can deduct the taxes you pay in Mexico from the US taxes you'll owe, you won't be paying more in total than if you only had to report the income in the US.
And I think you can deduct all the expenses on your US taxes, so that should lower your US taxes as well.