Hello student I'm sorry to inform you but you can't pursue M.Tech after BCA as M.Tech eligibility criteria says that - candidates must passed or appearing class B.tech or BE to get admission into M.Tech course with a valid score in GATE Entrance examination.

For more updates refer to the link mentioned below - https://www.google.com/amp/s/engineering.careers360.com/articles/mtech-admissions/

Feel free to comment if you have any doubt

Good luck