B.Tech

It is difficult but not impossible. Read the full answer it is detailed but getting admission during counseling rounds also depends on your caste and rank. See the last year cutoffs for various branches at NSIT. See can your rank get admission according to cutoff of last year. If you don't get NSIT don't get sad try for other good Colleges in Delhi. Fill the JoSSA form for counseling rounds. Fill the order of Colleges properly during form filling. Definitely you will get other good colleges if not NSIT. Take out the list of colleges and see there cutoffs. This helps a lot. Refer the link below for cutoffs of NSIT of all branch.
Lowest closing ranks is 22-23K. Highest closing rank is for CSE that near about 4300-4500. There are various rounds held play them carefully. Sometimes you get a seat in last or last second round so you have to patient. Good Luck!!

Mathematics- Arithmetic, Geometric, Harmonic Progressions, Binomial expansion, Successive differentiation, Maxima and Minimal, Differentiation of a function, Implicit function, Ellipse and Hyperbola, Parabola, Rank of a matrix, Elementary operations
Physics-Dimensional analysis, Heat and temperature, measurement, laws of electrostatics, Properties of matter, Waves and vibration, Rotational motion, Gravitation
Chemistry-Hard and soft water, types of hardness, disadvantages of the hardness of water, its causes, and its remedies and a brief introduction to the terms
Communication Skills-Words, antonyms, and synonyms, communication technique grammatical ability
General Awareness-General awareness about the country.