Nickel prices are slightly firmer as the deadline in labor talks at Xstrata's Sudbury plant approaches and further gains are likely, the nearer a strike possibility draws, a broker notes. Trade and macro players have been sellers on expectations that a deal would be reached but last-minute talks have so far failed to avert a strike, he says. LME nickel trades last at $36,400 a metric ton, up from a low of $35,600/ton Tuesday.