Yes , of course you can if you are determined and focused. I assume you are asking this because you are aiming to get a better college with JEE score while you have already joined B.Tech is a college to avoid wasting a year.This is possible but may not be that easy , it depends on your capability.You will have to handle both college exams, assignments and all other engagements along with JEE prep . You need to be extremely disciplined and study on a daily basis . It might be more rigorous than you expected at times ,so you should ensure that you won't flunk college studies, because remember in case you have to continue in the same college, a poor performance in the first year can put you under a bad light. Anyways , if you are confident it is possible , so set proper time table giving time for both college and JEE prep and stick to it. You can take online coaching for JEE .Practice a lot of mock tests to strengthen speed and accuracy.
All the best