can someone please explain why the values for Oi and volumes are different on Dhan option chain compared to the chain on Nse, which is accurate please help as I am new.
Yes, it may appear that there are few differences in Dhan Options. Chain & NSE Options Chain. Before that, I suggest you to go through this post
NSE shows volume & OI in terms of contracts i.e. Lots. Dhan shows volume & OI in terms of Quantity (= Lot x 50). You can multiply NSE OC volume or OI with 50 (for Nifty) and it will be equal to volume & Oi at Dhan Options Chain.
Dhan Options Chain is real-time. The Price, Volume & Open Interest changes as we get update from the exchange. NSE Options Chain updates only every 15-minutes.