I can't comment on code requirements. They are often rather surprisingly unintuitive.

From a technical point of view, I don't see any reason why this wouldn't work, though.

From a practical point of view, I would have to caution you, that your new oven might not get the use that you expect. We have multiple ovens in our kitchen and they are in constant use. Super convenient to have more than one. And even more convenient since they are all different types (CSO, SpeedOven, gas oven).

But I am 100% convinced that I wouldn't use them all that much, if I had to walk to a different room. A big part of their appeal is that they are right there next to where I am working in the kitchen anyway.

Thanks. Actually, we decided to put an electric range/Convection Oven in the garage, since it's only use would be for occasional large baking. We still need to install a 220 line, but that should be more cost-effective than adding a second oven inside the kitchen.

The only question I might have is whether there are any restrictions on temperature per the manufacturer. Cold might affect any glass in the door. Heat might affect any electronics.

If you don't care what it looks like, you can build a 'cabinet' with 2x4s and plywood. Ovens are designed for 0 clearance to combustibles. Remember that wall ovens are only finished on the front. The other 5 sides are unfinished.

My mom had a single wall oven, and it was not that expensive to cut into and revise the cabinet to accommodate a double oven. Have you priced another oven in your kitchen to be sure? My concern with the garage is more the dirt and other things in a garage that do not mix well with food.

Our new house had an unused 220-volt Outlet behind the gas range in the kitchen. I rerouted it 7-ft into the adjacent garage. We use a like-new 200$ used electric range, (top burners and oven), to keep heat and cooking smells out of the kitchen.

Added a new 20$ remnant (had to smooth the edges), 32” quartz counter over a new base cabinet and Bingo - an alternate “wet/hot” kitchen.

The TV and tiny fridge were only 40$ more from the person selling the range.

We wired a 50 amp outlet in my friends garage. It can be used for a welder or to charge a car. An oven shouldn't be a problem. We wired the whole garage. An electrician wasn't necessary.

In many places, such as much of NH, an electrician may not be required, but inspection by the Code Enforcement Officer is necessary (twice -- rough and finished), so the wiring installer better know what he is doing and, because not everything is always possible to inspect, have the confidence of the inspector. Confidence starts with the wanna-be DIY electrician acquiring a copy of the NFPA National Electrical Code Handbook and absorbing the content relevant to the job.

An inspector once told me that the purpose of inspections was to avoid the cost of lawyers.