At least in the US, nursing does not require a 4 year degree. You can become an RN with an associates degree. A 2 year nursing degree has one of the highest returns on investment of any training program (especially if you go to community college). Ivy Tech CC in Indiana and WGU both have nursing programs with great returns. Keep in mind, nursing is not an easy path and has a super high burnout rate. It's a tough and demanding job.
Other professions with a great return on training are HVAC, electrician, plumber, robotics/logic systems (CAM, conveyors, etc.). These are especially high paying if you focus on commercial and industrial.
Other professions with a great return on training are HVAC, electrician, plumber, robotics/logic systems (CAM, conveyors, etc.). These are especially high paying if you focus on commercial and industrial.