The number of seats available for branch sliding in NIT Raipur has been very few, in recent years. So, it's difficult to change the branch as most of the seats get occupied through the 7 rounds of JOSAA and 2 rounds of CSAB. Seats available for branches like CSE and ECE are the lowest. Due to the limited number of seats, competition is high for branch change. Students need around 9.6 CPI to get a good branch.
The factor about branch sliding clearly depends on which branch you want to slide in, and the vacancies in that particular department. It is based on several other factors too. Although, sliding in NIT Raipur is extremely competitive.
In fact, there are numerous students from average branches such as Metallurgy, Mining, Biotech, and Biomed, who put all their personal endeavors into sliding. Among which, there are students who succeed in doing so, and also there are students who unfortunately give up midway.
One of my friends attended NIT Raipur. During his time, the CSE department had only two vacancies, thus making it extremely difficult to get into CS. Branch sliding might not be as difficult as the preparation of JEE, but it definitely requires determination and quite a lot of hard work.
Despite all of that, your CPA should be at least above 9.2 for actually getting yourself into IT or ECE. However, for CSE it should range somewhere above 9.7 and for core branches, it should be around 9.5.