Nickel prices declined by 0.23 percent to Rs 923.90 per kg in futures trade Friday as speculators booked profits at existing levels amid easing demand at the spot market.At the Multi Commodity Exchange, nickel for delivery in October shed Rs 2.10, or 0.23 per cent to Rs 923.90 per kg in a business turnover of 7,298 lots.Analysts said profit-booking by participants at prevailing levels amid fall in demand from alloy-makers at spot markets, mainly influenced nickel prices at futures trade.