@tsjones,
You don't necessarily need an MS in Engineering unless you're looking to become a Professional Engineer (e. g. get a PE license). PE licenses are good but they are not easy to get. But my understanding (my father is a retired PE) is that the designation makes you fairly bulletproof. Not completely - if a company is wholesale laying people off, you might get it, too. But it's a big thing to have.
The question is whether you really want to do this. Another degree is a big commitment of time, money, attention, and brain power.