honestly I would dilute it and then add more sugar later. To much sugar is just as bad as not enough nutrient. The yeast like sugar but to much kind of puts them in shock. I would estimate your PA is between 16 and 17% the yeast you are using can handle that kind of alcohol content but until the sugar content goes down it will probably be slow. Yeast nutrient won't cause your yeast to die to fast. the yeast will reproduce and die as part of the process. nutrient will effect that but not in an all or nothing sort of way like you suggest.
- "It's all about time. You can't rush perfection. Time TIME TIME!!! You either need to pay on the front end or the rear. If the batch ferments out fast you need to secondary age or bottle age it. If it ferments out slow... months not weeks, then you don't have to age it nearly as long to get good flavors. Either way time is the key when making ciders and wines."