Hi!

The tan color you are looking for is in Mecabricks. In fact, it's the default color when you open the workshop. Older colors generally have two names... the community name and the official Lego name. This is because Lego used to keep their color names internal and private. At some point they released their color naming conventions but the old names stuck. From that point on, community names generally follow the Lego names.

So tan bricks have two names... Tan as a community name and Brick Yellow as the Lego official name. You can see this on the link you listed below. Scrubs has organized his colors based on the Lego convention, so you will need to look up Lego names and ID numbers. If you scroll down on the link you posted, look for Lego in the System column. This shows you that you're looking for color number 5, aka Brick Yellow.

Here's a chart of all the colors:
https://www.mecabricks.com/docs/colour_chart.pdf