M sale long term capital gain froof nifty linked debentures

Not possible, since long term capital gain is exempted in your case.

According to me in  your case Long Term Capital Gain arising from sale of Nifty Linked Debentures is taxable in your hand, since what is exempt u/s 10(38) are  Long Term Capital Gain arising from transfer of Long Term Capital Asset being an equity share in a company or a unit of equity oriented fund, where the transaction is chargeable to Securities transaction Tax.

Since in your case its Nifty linked Debenture so the Long term capital gain arising from its transfer is taxable and accordingly you can set off your Short term Capital Loss arising from sale of equity shares against long term capital gain arising from sale of nifty linked debentures.