I got 19796 rank in viteee what are the chances of getting cse in vit vellore?

Yes, you can get CS branch in Vit Vellore with this rank. But the fees may be higher. There are various categories of seats in vit vellore.
With this rank you will come under 2nd or 3rd category and for that fess is generally higher. Your fees will be around 2-4 lakhs per annum. Also if you want to take admission at a lower fees then try for other campuses like bhopal, Chennai etc.