Full Time MBA

Yes, you can do Both M.Com and MBA degree together if you will do one degree from regular University and another degree from distance university. You cannot do both degrees together with regular University. Also, you cannot do two degrees together from one university at a time. Yes, but you can do two degrees together in Distance education.
If you want to give more preference to MBA, then you can do MBA from regular University. You should do MBA through full Time course. M.Com is general Commerce degree, so you can do it from distance Education. The value of M.Com through distance education is same as Regular.
You should do MBA Full Time course and M.Com Part time course. You have to get admission in IGNOU in M.Com and go for CAT/MAT/XAT entrance test for MBA. In that case, you can get both degrees together in same time and your MBA and M.Com both degrees are valuable.