Hi Andrew.
Welcome to IceInSpace
Congratulations on a great scope purchase.
I agree with wavytone. Dont write off your supplied plossls.
However, for when you have more money than you need ...
For my 10" DOB I found my Televue Panoptic 27mm was best for most (large) DSO's.
For a cheaper alternative I found Vixen LVW's to be nearly as good for a lot less.
The 13 Nagler will be a good general eyepiece (very very good actually)
And as Wavy said 4 to 6mm for planetary detail. Here, plossls are a bit tight, so I have used TV Radians (but these are no longer sold new). Alternative, use a good barlow with you 13 Nagler might even be better.
Once you have studied Saturn and Jupiter, I don't think you will have much use for high magnification, so seems a bit of a waste to spend too much on this end of the range.
Too many choices.
See if you can find a local observing group and see what they are using, and test them in your scope.