The third-seeded Almagro needed just over an hour to clinch the title and carry some momentum into next week's French Open.
Almagro cruised Saturday, winning the final three games of the first set and breaking Baker's serve twice in the second set.
Despite the loss in the finals, Nice was a success story for the unheralded Baker. He came into the tournament ranked 216th in the world and was out of competitive tennis for nearly six years due to various injuries including elbow reconstruction surgery.
Baker, who was playing in his first ATP tournament finals, earned an at-large berth in the French Open and will play Xavier Malisse of Belgium in the first round.