Dwarf nectarine tree

Potted plants always need regular feeding as they quickly use up nutrients in their confined space, so some chicken pellets and bit of BFB meal are good choices, as well as regular watering with a bit of compost tea.

Nectarines can be treated like peaches and are normally self-pollinating. Your tree might be reaching bearing age this year, or next, and here's something about pruning which is unique to nectarines. This is taken from Garden Central:

"Prune With A Vengeance -If you do decide upon a nectarine tree, or several for that matter, be aware that they require fairly heavy pruning, more than your typical fruit tree. Fruit is set on one-year old branches, so once your tree begins to bear fruit, heavy winter pruning should result in a bumper crop. Don't just take a few snips here and a few there. You want to cut away at least 60% of the previous years growth. Also prune so that the center of the tree is fairly open, and has no crossing branches. This is good practice with almost any fruit tree. By keeping the center open, you may be able to avoid brown rot, a somewhat common disease affecting nectarine and peach trees. Besides providing delicious fruit, most varieties of the nectarine tree will put on a flower show for you each spring. They also make a nice ornamental addition to the yard or garden. If you purchase a single tree only, don't worry about pollination. Unlike some fruit trees, you only need to plant one to get fruit. All that is required is a visit by some bees at the appropriate time. When fruit starts to develop, thinning is a good idea. Use your judgment. You'll get larger fruit for certain, but also avoid the possibility of broken branches as a nectarine tree is usually a very heavy producer. You can prop branches up of course, but thinning is far and away the preferred approach."

I have peach trees but they don't require such heavy pruning. But they do need the fruit set thinned out as I did have a big branch snap last year from too much fruit weight