The towering Nigerian finished two second-half goals with style to impress early in his MLS career.
Fanendo Adi scored the game's first goal in the 65th minute. Breaking forward, he confidently turned Jorge Villafana's low cross towards goal and past Dan Kennedy.
He scored his second just five minutes later, beating the offside trap and meeting Diego Valeri's excellent through ball. He passed Kennedy and with Chivas defenders chasing back in panic, calmly slotted home.
Things got worse for Chivas USA in the 84th minute, when Bobby Burling heavily fouled Adi and traded words with the Portland bench. The defender was quickly shown a red card.
The Timbers have now won back-to-back games and are undefeated in their last six matches. They now have a 3-3-7 record. Chivas USA is 2-6-4, last in the West.