Yes it's possible. If you thoroughly prepare for UPSC then surely you can give the MPSC exam too. In MPSC exam language subjects will be subjective and the other 4 will be objective type. Both the exams almost have similar syllabus. Both these have two subjects that is CSAT and the General Studies. The difference between the two is CSAT in UPSC is just qualifying.

Check out the syllabus of both the subjects by clicking on the links below..

https://competition.careers360.com/articles/upsc-ias-syllabus

https://competition.careers360.com/articles/mpsc-syllabus

Best wishes. Thank you.