Fund transfer via NEFT is chargeable both via Nest and Mobile App - Charges differ from bank to bank and in Nest before the transfer, you would be able to see the exact charges that would be applicable for the transfer.
In Nest, NEFT is the only available option however via mobile app, you can transfer funds via UPI and Direct Access (from linked Kotak Bank) which is free.
Below is an example of the fee breakup for transferring funds through NEFT.
How long do funds take to reflect in my bank account after I request a payout?
How long does it take for deposited funds to reflect in my trading account?
Can I make an NEFT/RTGS transfer from someone else's account? (third party transfer)
Can I make an IMPS/NEFT/RTGS transfer from an unlinked bank account or someone else's account? (third party transfer)