The reason for the NOC code question is because the 2nd digit of the number tells you if you are skilled or not. If the 2nd digit is 0, 1 or 2, you are skilled. For example if you are 6241 chef or 6242 cook, you are considered skilled.
In AB, you are eligible to apply under PNP as a cook after 9 months of work plus some other conditions, see
http://www.albertacanada.com/immigration/immigrate/cooks.html