AD or AS nocturne? ( can skip to the nunu)

So I was just in a game. got flamed for going AD/lethality nocturne cause "i was useless in teamfights" even though I would 1 shot two or three people every time (on an all AD team may I add. but everyone had a main souce of armor pen ) I was flamed for like 10 minutes for not going attack speed (went and got as they had one shotting AP this I got before the flaming) even though I have a 40/80% attack speed bonus and wits end with a base of 1.5 attacks a second without my doubled AS passive though last time I did AS nocturne when he was free I would go 1/12/something. AD lethality I have done 6/0/1 21/10/4 7/5/15 (would like to point out I feel I have a tendency to get or on the enemy team. both of which I am not TOO good against and limit my kill potential but still did ok) as AD lethality nocturne AD lethality has a lot of perks for nocturne. helps with initiating helps with chasing or landing fear ...well his ult. that and your going AD lethality. so your ult does a ton of damage and lets you come in with some true damage lets you duel easily, and if they try to CC you then you just go on them with high attack speed and if your full on the lethality/warriors then your attacking with high attack speed and 500 AD Now if you look me up lets get this outa the way...my winrate is horrible cause I'm getting stuff like / top picking then the enemy goes support, illaoi support (which I have been running into a lot for some reason...) 1/8 laners and all that...Though anything with that was probably me or a now after spending who knows how long defending my 35% win rate from others (one death my laner has 5 kills all that...) the main question. AD or AS? I haven't done good in an AS nocturne game but when I went AD (after a month or so after never playing nocturne) I was doing pretty good. one thing I didn't get when I was getting flamed is why AS would make me better in teamfights then AD when I can just do a ton of damage with my ability's his ult also has a good AD scaling of 120%. so you can just walk around with a 900 damage ult to play a little magic trick on the ADC or support.