I don't see any nickels.(But for all I know you dug 20 push/pull tabs!) Have you ever tried going to that spot and working the nickel tones? I started in this hobby in 1984 myself and have found plenty of silver masked by nickels in "worked out" areas. Not too long ago I worked a curbstrip that was super clean. No targets anywhere, except two. One was a war nickel with a merc sandwiched to it down about 6 inches. The other I thought maybe was a chain as it was a wide faint tone and I had recently dug an old gold plated brass pocket watch chain that acted very similar. I swept over it moving around to decide where to dig...first coin out was a silver quarter and it was down with three nickels that were spread out several inches. I was using the at pro and both of these targets were mid tone. No inkling at all that I was digging silver.
Anyway, if you haven't, you could be in for some nice surprises out there.
Anywho....grats and good luck next time out.