Dear student, with an AIR of 245 in the GEN category for NIPER M.Tech, it's highly likely that you can secure a seat. However, the specific NIPER and specialisation depend on the cutoff trends and your chosen field. Usually, ranks up to 150-200 are considered good for top NIPERs like Mohali, Hyderabad, and Ahmedabad, but your rank is close enough that you have a good chance in these institutions, especially if you are flexible with your specialisation.
Dear student, you can attempt NIPER mock tests on various test-prep sites online. The official mock test has not been released yet.
Dear student, Indore Institute of Science and Technology offers a Merit-based fee structure for the first year and IIST Merit scholarship plan from second year onwards. You may check out more details about the scholarship plan here - Scholarship Plan of IIST.