In large bowl, mix 1/4 cup olive oil, the barbecue seasoning and 1 teaspoon salt. Add potatoes and onion; toss to coat. On each of 4 skewers, alternately thread potatoes and onion, leaving 1/4-inch space between each piece. In same bowl, place chicken; toss with remaining oil and seasoning in bowl. On remaining 4 skewers, thread chicken.