I climbed the NE summit, climbing from the east side of the mountain and a 5680m high camp. No real difficulty for reaching the top, it took me 6 hours.
We found a good campsite at 5,400m on the NE side of Nacimiento having spent a long day with heavy packs walking from El Arenal. The next day it took 4 hours to climb up a shallow gulley to the NE summit. We then descended to the col at 6,350m and climbed the true NW summit - this took a further hour.