This app was mentioned in 4 comments, with an average of 3.50 upvotes
Been using xkcdViewer for the last 9ish years. Hasn't failed me yet!
Lets you tap a comic to view alt text, open links (on comics that link to something like a higher res map/image), browse by number (or random), search by title, or open the explainxkcd page for a given comic straight from the menu. Also has a favorites system.
I don't know about using chrome, but if you use Android there's an app called xkbdViewer where if you tap the comic it shows the tooltip text.
Google Chrome, Sync for Reddit or an app like this