ESRI Australia developed a very good Widget for displaying Nearmap imagery. Simply enter a valid API key and it will display the Nearmap imagery from your subscription. It even integrates a swipe function for comparing imagery of various ages. It's great!
...And with the Experience Builder 1.19 update, it's broken. At least, that fancy swipe function.
I have re-built the swipe functionality using a graphic layer that can be clicked and dragged. I have also added a numeric input and a slider inside the Widget interface and migrated the Widget to use Components.

Note: You must be a paid Nearmap subscriber and obtain a valid API key from Nearmap to use this Widget.