HMTLCollection
HMTLCollection interface is a collection of elements and methods and properties that can be selected from the list. HTMLCollection is live in the HTML DOM and it is automatically updated.
NodeList
Nodelist are objects of colletion of nodes, and there are two varieties of Nodelist. One is live and the other is static; live is when changes automatically update in the DOM. Then static is changes in the DOM will not affect the content.
Differences and/or Similarities
One key difference is that NoneList contain any node type and then HTMLCollection only contains element nodes. Similarities between both are that they both are similar to an array which contain nodes, then remove them from the document.
Summary
HTMLCollection and NodeList are very similar with minor differences that can used for specific needs. Both similar format which makes it easy to understand how to get what you are trying to get from it.