No way it is going to affect your chances....the CIC policy objectively decides on cases and as you will meet their requirements there is nothing to worry at all.
1. If the said NOC0 experience of 1 year is continuous,paid, permanent,full time working minimum 30hrs / week ,and is within last 10 years. CIC policy requires you to have worked in the chosen occupation in the last 5 years...so if the said experience is not older than 5 years at the time of eAPR then you are fine. Make sure the duties and responsibilities mentioned on the experience letter match to a great extent to the ones on the NOC's listed duties and responsibilities as per CIC
2. 1 year experience gives you only 25CRS points...so if you chose the above NOC as primary NOC, you still can add other unrelated work experiences for gaining points... if you have another 2 years experience among different NOCs add them as well as that will give you 25 points more...the only thing is you need to have the reference letters and proofs of employment and duties should match with on the NOCs...and in worst case scenario they will only decline those experiences if they are not satisfied with the reference letters ....(if u can produce reference letters as per CIC requirements you can add up unrelated experiences...)...
Ur primary NOC will remain the first one..
experience beyond 3 years don't fetch any points so don't bother beyond that...and, experience from 1 yr 1 months to 2yrs 11 months carry only 25pts,so if your second or third experiences can't still take you complete 3 years of experience,don't bother also...
there's nothing to worry on the point you worry at the moment...