I know how to nudge things around in the Timeline, but as I use a lot of still, titles and shapes, are there any tools that allow me to similarly nudge things around in the Viewer?

What exactly do you mean in the viewer?

here

You can't do it with the keyboard (not to my knowledge), but you can fine tune an element's position in the inspector under the Transform parameter. Select your image, activate the Transform tool (Shift-T), then you can adjust the position, rotation, scale, and anchor point. Holding down the Option key while dragging on the numbers adjusts in smaller increments.

Actually when working in the Inspector, you do not need to activate the Transform tool at all.

But here's how you do it, and it must be done in the Inspector. Click once on either the Position X or Y numeric parameter. Use the up and down arrow keys to nudge one integer at a time.

Any Inspector parameter pretty much can be nudged like this.

As mentioned above which is almost the same just have select the direction.

BenB wrote:
You're right. When I tried this last night it required me to activate the Transform tool. I guess the viewer wasn't responding for some odd reason. Nice tip though on the arrow key nudging, Ben!

As an added bonus, you can also use the Tab key to select the next parameter. If you need to go back to the X parameter after Tabbing over to the Y parameter, use Shift-Tab. This is a system-wide shortcut really, but it'll keep you from having to use the mouse to manually select the parameter you want to adjust.

I like to use the mouse wheel for change values.

(my first post here

Magic Trackpad, myself. Have hated mice since.

Once you click the X or Y (or any parameter such as scale, angle, crop)...

...as well as using arrow keys to increase or decrease by 1,

you can use Shift with the arrow keys increase or decrease by 10,

or use the Option key to increase or decrease parameter values by 0.1.