You are best to post a floorplan so you get help as there could be an interior space that will work just as well and cost a lot less. Can you install pantry cabinets instead of a walk in pantry? Also in my opinion the cost of something like this into a garage may outweigh the benefits.

First it would not be advised since it would require opening an exterior wall to do so. Your garage is an addon in the building usually . You have a small garage now and cars are just getting bigger so IMO not a good idea. Yes we need a to scale floor plan to honestly answer this question. Use graph paper to make scale drwaing easier and show every window , doorway where those lead and every measurement clearly marked. Then the kitchen cabinets and appliances as they are . Show where the garage meets the kitchen too. Post here in jpeg format in a comment . Post pics of the kitchen too , that will help us help you.

How deep is your garage? What will be the finished dimension if you take a foot of space from it. We seldom design garages with less than 24 feet of depth. That should accommodate even larger size vehicles.

Our first house had a standard depth closet taken out of the back of the garage. Since the car we chose to keep in the garage was a small VW, it didn't matter. We didn't even have to move the workbench that was on the garage side of the closet. However, I can see it being an issue if a 'normal' sized car no longer fits. However big that is.

You could show your kitchen................

Would not recommend taking away from the garage but a dimensioned floor plan is needed to provide any sort of assistance.

It depends on the configuration of the garage. I thought about possibly a bump-out for laundry room remodel but then realized that even though technically there's enough space in the garage, the way the entry door is positioned and cars are oriented, it would be an extremely tight squeeze to enter the house and would cut off access completely from one side of one of the vehicles.

In your case, unless it's a really large 1-car and the configuration of it allows for it, I would not do it. A 1-car is already plenty small and yes it might affect resale -- your car may fit but the next owner's may not. Even then, it's if that large you'd get better resale value from enlarging it a little more to be a 2-car compared to a pantry.