That is the board, and the jumper is exactly as it is in the picture. So here's the complicated thing about this board, and maybe I've been doing something wrong here all along:
Originally, I connected the VCC pin on the Relay board to the 5V pin on the Arduino, I connected the GND pin on the Relay board to the Ground pin on the Arduino, and then I connected a digital pin to the IN1 pin on the Relay board.
Here's where it got confusing for me: so my goal was to be able to write a HIGH to the digital pin, which would trigger the contacts on the relay, and the door would open (the two wires for the "request to exit" would "touch together" for just a second. I couldn't use the NC contacts on the relay board, because I didn't want the door to be open if the Arduino wasn't powered, or if the digital pin was LOW.
So I thought it would work the way I wanted it to work, by putting those two wires (from the "request to exit") into the NO pins. Great. Arduino has no power, the wires aren't connected. But as soon as I plug in the Arduino to power, the wires were touching. Why? Well, the relay board works like this: when the IN1 (or IN2) receive LOW, the relay activates and the wires were touching. When I set to the pin to HIGH, the wires were no longer touching. Well, ok, so I guess my program needs to constantly keep the pin HIGH (to keep the door locked), unless I write the pin to be LOW for a second, opening up the door. Well, not so great, cuz what happens if the Arduino loses power, the relay deactivates, and the wires are touching, and the door becomes unlocked!
So I came up with an idea: use a digital pin to supply the power (VCC) to the relay board. This way, the wires in the NO pins aren't connected, and when I write the pin (connected to VCC on the board) was set to HIGH, the relay activated, and the wires were touching.
This worked great on the Uno, but it didn't work on the Nano.
So what's the difference between the two? The .31 difference in voltage? The LED on the relay board would come on, but the relay would never switch (never heard the clicking sound).