Nickel prices are set to stay firm as long as supply worries continue, broker says, noting the potential loss of at least 1,000 metric tons of metal if a cracked container ship adrift in the English Channel sinks. This is equivalent to one-fifth of the world's London Metal Exchange nickel warehouse stocks. The looming deadline for a strike at Xstrata's Sudbury mines is also adding to momentum although there's no certainty it'll take place, he adds. LME nickel trades last at $35,745 a metric ton, down from the market's all time high seen Thursday of $36,050/ton.