Here is your build with an RX 480 added, PcPartPicker shows system requirement as 299W. If you add an RX 460 it is 224W and a GTX 1060-6GB is 269W.
The FSP 400W hexa+ is not a horrible PSU,
http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story6&reid=341
It should do for this build if you already have it.
PCPartPicker part list:
https://pcpartpicker.com/list/WYnKbj
Price breakdown by merchant: https://pcpartpicker.com/list/WYnKbj/by_merchant/
CPU: Intel Pentium G4560 3.5GHz Dual-Core Processor ($59.99 @ SuperBiiz)
Motherboard: MSI B250M MORTAR Micro ATX LGA1151 Motherboard ($82.99 @ SuperBiiz)
Memory: G.Skill Ripjaws V Series 8GB (2 x 4GB) DDR4-2400 Memory ($58.99 @ Newegg)
Storage: Western Digital Green 120GB 2.5" Solid State Drive
Storage: Seagate BarraCuda 1TB 3.5" 7200RPM Internal Hard Drive ($49.77 @ OutletPC)
Video Card: MSI Radeon RX 480 4GB Video Card ($185.66 @ Jet)
Total: $437.40
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2017-03-31 06:44 EDT-0400