What component allows cursor movement via a small joystick-like nub?

The component that allows cursor movement via a small joystick-like nub is known as the Trackpoint. This device is often found on laptops, particularly those from manufacturers like IBM and Lenovo. The Trackpoint is situated between the "G," "H," and "B" keys on the keyboard and allows users to control the cursor's movement by applying pressure in different directions.

It operates based on pressure sensitivity, meaning that the harder you push it in a specific direction, the faster the cursor moves in that direction. This design can be particularly advantageous for users who prefer a more compact way to control the cursor without having to reach for a separate mouse or touchpad.

In contrast, a trackpad operates by detecting finger movements across a flat surface, and a digitizer is designed for inputting information through touch, primarily used with styluses or touch-enabled screens. An accelerometer detects changes in the device’s orientation, which is more related to motion sensing than cursor control. Hence, the Trackpoint stands out as the correct answer for enabling cursor movement through a joystick-like mechanism.