PCIE 16x are all the same, so it will fit in that regards, but I think that PC is a slim form factor? probably isnt wide enough to fit a GTX1060 unless your are interested in cutting some metal and having your GPU sticking out the side. In addition to that the power supply in there defintely isnt strong enough to run a 1060.
You should look into a low profile GTX 1050ti such as https://www.newegg.com/Product/Product.aspx?Item=N82E16814137081 if you want a GPU upgrade, you should make sure your power supply is strong enough though.
300w with a 1050ti is ideal, 250w is very much so on the edge of whats safe.