Spieth, who started at No. 10, had two birdies (Nos. 12 and 14) and one bogey (No. 15) on his first nine.
As he made the turn, the projected cut was 1-over. Spieth tied for 16th in last year's Nelson and is hoping to better that feat in 2011.
He birdied No. 12 by putting from off the green, conquering a hole that bit him on Thursday. He double-bogeyed the 12th in the first round after hitting in the trees, but played the hole from the comfort of the fairway on Friday.
Spieth's second shot spun back toward the hole at No. 14 to just over 2 feet for an impressive birdie. He found himself in the thick rough by the green on No. 15 and his chip was short of the green, yet he managed to then get up and down for bogey. He missed an 18-foot birdie attempt on No. 16.
Spieth is beating his two playing partners, Daniel Summerhays and Bobby Gates, who need some birdies on the second nine to make the cut.
Spieth has plenty of support, playing in his hometown. Plenty of Jesuit seniors and teachers are on hand, along with a gaggle of family members.