I really like cinnamon and nutmeg. I'm sure there are other spices like cardamom would be wonderful.
I like nutmeg, ginger, and allspice with my nectarines. A touch of cardamom will also add a nice level of flavor. I once added some chopped pistachios to a nectarine crisp and that worked really well. What are you making? I bet it's delicious!
Cardamom is a new-found love with nectarines. I added some cardamom to simple syrup-packed nectarines that I canned last summer. I opened them recently and they're lovely. Turning that puree into cardamom-nectarine marshmallow was even more heavenly!
Have you considered any herbs? Any of the lemony ones would be nice, plus I think thyme or sage might be good.
mace would work well. I'm just guessing, it kinda smells good to me.. (the synesthesia is acting up again!! ;-))
Once when I was trying to make scraps into a last-minute meal, I macerated nectarine slices in just a little of that syrupy Mexican vanilla. It was sensationally good. Now I like to serve with a little sprig of fresh mint and a dollop of whipped cream.
Nectarines and basil are made for each other - divine.
I adore nectarines and have tried everything to have that taste year round. I have failed at canning them because they have so much fiber - more than peaches - and it is labor intensive to try to peal them. And the skin is too tough for my taste in canning, although amazing raw.
I have had the most success with dehydrating nectarines. No peeling, just pit. And the peel has the same texture as the fruit which is quite pleasant when dehydrated. And the sugar stays in.
I have seen a recipe for nectarines with lemon verbena.
I love basil and anise, for a mysterious (but delicious) grassy effect. Cardamom and lime juice for a very open bright flavour. For a more wintry feel, mulling spices go amazingly well with nectarines. What are you making? :)
Peaches pair well with curry powder, and I'd guess nectarines would too. This isn't a dessert, but an accompaniment to ham, roast pork or turkey: Cut in half/pit and roast them with curry powder, grated ginger, a little brown sugar or honey, s&p, a squeeze of lime or lemon - delicious with ham, roast pork or turkey.
I also bake peaches - again, nectarines might be a good variation - in Marsala or Port (sherry or Madeira would probably work too,) with sugar, vanilla and some lemon peel. When they're done, you reduce the liquid left in the baking dish to a syrup and cool everything together. Great dessert with a dollop of creme fraiche or vanilla ice cream - Greek yogurt would probably work too. Also a good make ahead - more delicious the next day.
Oops. Just thought of one more: I've made clafoutis with plums before, so why not nectarines? I'd think any stone fruit would be delicious. When i just looked for Julia Child's recipe online, I found a blogger's variation with peaches and ground cardamom - sounds like it would be good with nectarines too: http://sugarandspice-celeste.blogspot.com/2010/08/peach-clafoutis-julia-child.html