I have a nectarine tree. It had fruit on last year and was fine this year, 2018. It's now 29 April and no sign of leaves or any life. It's got some very small buds on but that is it. I am beginning to wonder if it's dead, or could it be we had a colder winter this year? It was in a pot in the conservatory over the winter, which is quit warm. Now it's in the green house.
Do the branches bend or snap off?
Do a scratch test on the bark.
Did you have a cold snap after buds had been set? This can often happen and the buds will die off in the cold.
If this was in too warm of an environment you may not have had enough chill on the tree to produce buds.