Watson is a giant of striker from Conference outfit Margate Town. The bigman signed for the Kent side last October after he was spotted in the Irish leagues.
Robinson was released by Chesterfield last season despite having limited success following his free transfer switch from Derby, in fact he made his Chesterfield debut as a late sub in the 4-0 defeat at Blundell Park last September.
Nicholson has bags of experience despite his age of just 23. He may be better remembered for his role in the ITV documentary a few years ago highlighting the ups and downs for young professionals. Also featured was then Leeds striker Alan Smith. Slade will no doubt be well aware of Nicholson's abilities having signed him on loan for Scarborough last season.
Riley too was released by the Magpies at the end of last season. Aged 21, Riley has started 18 games for County netting a rather impressive 3 goals.