The 29 year old was minding his own business as he made his journey to Bolton Central Fire Station when he noticed a woman calling for help for her granddaughter had stopped breathing.
The 18 month old was in good hands as Nicholson came to rescue the poor infant by giving her the kiss of life - a skill he had learned from his CPR course only two weeks before.
The fireman was pleased to help the woman and the baby's mother who was frightened to death, standing near by at the thought that her baby might die.
The toddler was taken to Bolton Hospital, and stayed in over night as a precaution. Nicholson has said how quickly the baby came around. "She had stopped breathing and was turning blue so I began CPR - pressing her chest with my finger 15 times and then I got one breath into her mouth."
The child's mother, Ms Lorna Smith has said that her little girl had been ill recently and that they were returning from the hospital when they noticed the child turning blue.
The family were very grateful that the fireman was passing by. "He was cool, calm and just took over."
He was just pleased that he could revive her.