My SAT score is 1850. Can I get admission to NIT, Surathkal in the IT branch?

Firstly, congratulations on scoring this in SAT. The grading here is quite relative. Normally, the state toppers, IIT 3000-8000 rankers, 96% to 98% CBSE scorers will be your immediate competition with your rank of 1850. Although, there are good chances that you might have to wait for a few rounds to finish and then maybe in the third or fourth round you might get lucky.

The rank mentioned by you here is quite a fair enough rank. It is also advised here that you have a look at SAT scores as well for the past academic year. There is a slight trend that the scores might vary every year depending on overall performance of all applicants.

Since much shuffling and reshuffling takes place in all the branches including IT in all the admission rounds, it is worthwhile that you wait a longer and try in the third (or fourth) round of counseling.