You’re pretty definitely not gonna be able to find any real-life armor that looks like it. I just asked my partner for tips on what to search for (as she’s the more military-savvy of us), and she ended up rambling about how chest armor should be a single piece, and not split in the middle. XD However, I did find something close-ish from her recommended search terms: https://www.gijoesmilitarysurplus.com/index.php?main_page=product_info&cPath=1530_1649&products_id=15620
It’s not quite the same, but it does have multiple plates in the front, and is split in the middle with a zipper. There might be other sci-fi franchises with closer designs, but I’m not personally aware of any. If you really want it to be plastic rather than foam, and don’t have the setup to do it yourself, you can also try hitting up folks in the Star Wars 501st (who have really high kit standards) to see if you can commission them (or someone they know) for the chest piece.
The cheapest choice is like @FormlessBlackVoid said–check out tutorials, get some thick foam, and build the chest yourself. If you don’t want to freehand the shapes and have a printer, you can blow up screenshots and print out a few pages to trace from. This would take a lot of ink, though, so if you have a light hand and a sufficiently-sized monitor, you can try gently pencil tracing from zoomed-in shots on your computer. (Be very careful, if you press too hard you can damage your monitor. Thinner paper will make it easier to see the actual shapes you need to trace.)
Also, if you have/decide to add pouches and/or a pack to carry stuff in and plan to wear it to a convention or the like, I recommend bringing duct tape! (And munchies, and your preferred glue, and a first aid kit, and… :D) I took photos with a bunch of Junkrats last year while cosplaying a warboy from Fury Road, and one of them had a strap that came loose and was fraying. If you or anyone else you run into have a strap come loose, duct tape will let you keep it in place until you get a chance to fix it properly.
And hey, when you get it done, I’d love to see photos if you’re willing to share!