In mountain warfare, it takes very less men to defend than to attack. In order to capture territory, China would need to block/disrupt our supply and logistics lines, for which they need the PLAAF. PLAAF would need to fight over Indian airspace in such a case, and that would mean heavy losses for PLAAF, with India's fighters and ground AD units (SAMs and AAA) defending Indian skies.
Similarly, it will be quite difficult or India to conduct an offensive due to the same reasons.
Also, due to the nature of the terrain, armored warfare is not possible. So it comes down to infantry. By blocking the major passes, India can hold the PLA troops. Also, they can let them come forward so that their supply lines are extended and then strike the supply lines from the air, cutting the Chinese troops off and bagging us a bagful of POWs.
If there is a conflict, it is not likely in the Tibetan region, as neither India nor China can sustain the offensive and make tangible gains, while keeping acceptable casualty levels. Conflict would more likely be in the NE states borders.