I have a BS/CS and MBA. Most employers look at the wall paper first, and the granting institution second. If you have a top tier education on either degree, great. If not, the letters MBA subtext useful content and they are considered valuable.
MBAs are easy compared to any engineering degree. You should be able to waltz through one if you want to. You can find some cheap ones, if you look. These days, you don't have to look too hard to find one that is cheap, fast, and by YOUR standards, a cake walk.
I'm at the end of my career and can tell you that in my case, it was totally worth it. I learned useful content, perpetual issues, basic concepts, and most importantly, economics.
One thing that made me a more competitive engineer than engineers from top tier schools was that I understood how economics is an ever present constraint for any problem. It amplifies and illuminates the technical aspects. It also helps with self employment and retirement planning, not to mention quantitative evaluation of alternatives, which comes up like 100% of the time in any engineering question.
The business majors who took the easy way out and got an BSBA often wound up in management positions. Hell, half the business leaders I worked for were not even college grads, even at Lockeed-Martin and Raytheon. If you are an engineer, you took the hard way through, and you will, if my experience is any guide, routinely lose out to folks who have less tech and more business/marketing skillz.
So no shit. I absolutely guarantee you can do it, and suspect you'll get a 4.0 GPA while working full time. (I got a 3.9 and worked full time when I got mine.) Companies lust for folks with tech smarts, math smarts, marketing smarts and the vocabulary to communicate them to managers and clients.
If you don't know that debit means left, that an income statement is different than a balance sheet, what corporate forms are, etc. you will lose to me in an argument.
I can't tell you how many tines I've been able to play the card "I'm the one with the MBA here and can help you understand this if you would like". How many times I've been asked what my opinion is over the Georgia Tech EE or the MIT guy. Or how many times I've been able to tap into what all those financial issues are that relate to my project, my products, my personal life, my retirement, my plans for being self-employed. It's totally worth it.
So... IME, get an MBA. Get one from top tier, especially if you have top tier undergrad engineering degree. If neither, a combination of cheap BS and cheap MBA are still a good combo.