Of course, IE itself has some business-adjacent course work (engineering economics and finance, operations research, data analytics, manufacturing processes, human factors) anyway, so an entire second major in business may not be necessary to learn everything contained in that major.
But some opinions on the matter have already been posted in your other thread: Berkeley OOS [$79k, mech eng] vs Gtech OOS [$52k, mech eng] vs Emory [$38k, business + engineering 3+2 with GT] - #12 by HTTC24