450 is technically enough, if it's a decent psu. The 2060 has the same power draw as a 1060, and a 95w cpu is chump change average.
That whole pc will pull @300-350w depending on levels of oc/boost from factory, but you do not really want to include any user OC on top of that.
That Seasonic 400 is a great psu, for an OEM bulk psu, it's only real rival is built by Delta. But it's not designed for the instant, heavy draws a gaming gpu can and does slap it with. It's like trying to make a work horse into a race horse, not gonna last for long.
At @ 250-300w average gaming draw, your best area is a good 450w to 550w psu. This puts thermals, efficiency, power consumption right at the 50% range, which is where psus work best. The 450w psu can live easily at closer to 75% draws.
You'll spend @ $50 for a decent 450w or @ $50 for a decent 550w, really a no brainer.