I am a nurse and need to use my watch to count by seconds. How do I do that with my Apple Watch?

Also change the duration that the watch face stays elumated

Apple Watch -> Settings -> General -> Wake Screen -> Wake for 70 seconds

NOTE: You can use your iPhone -> Watch app to arrange your watch faces in any order you want. Then you can swipe left or right to switch watch faces. So if you have your normal watch face adjacent to the watch face you use for counting seconds, you can easily just swipe left or right to switch.

There are several watch faces that include seconds, either digital or a sweeping second hand.

You can also use the stopwatch for counting seconds.

There are multiple analog face configurations in watch face settings.

Change your watch face to this;