Is there any way to get the right bootloader to make it compatible with the UNO?
I thought the Nano and the UNO used the same bootloader.
The best way to do that is to select Tools > Board > Arduino/Genuino Uno before you do the Burn Bootloader. This is a little bit confusing because you have to have the Nano selected from the Tools > Board menu to upload the ArduinoISP sketch to the Nano, but then when you are doing the Burn Bootloader step you should select the board associated with the bootloader you want to burn to the target chip.
The thing is, it works perfect in a breadboard. So I don't know what could be causing this error. It's like my Uno doesn't even recognize it.