How to reset the mileage range estimate on the console of a Mitsubishi Montero it reads 32 miles left even with a full tank of gas?

You have to put in more than 10 Gallons of Gas to get the system to reset and reestimate the miles to empty status. Since you have a full tank, either you have some bad circuit or sensor (call a dealer), or I would run it completely down near empty, and then put in 10 or more gallons and see if it resets. Perhaps it has gotten confused.