You have a lot of options for a decent lunch, all within a mile or two.
North of IKEA, on the route 1 corridor in Beltsville:
There are two pho places, Pho 88 (in the Petco shopping center), and Pho Vn One (in the shopping center across from Costco). 88 has been somewhat inconsistent recently, but still has its good days (even on its bad days, it's never terrible). Pho Vn One just opened two weeks ago; but based on two visits it's a very good option.
A Korean noodle shop, Myong Dong, at the corner of Rt. 1 and Powder Mill Rd., is family run, very homey, delicious and cheap. There aren't very many choices here, but you don't need many. A bit further north, also on the left, is Gah-Rahm, an ambitious, sprawling Korean bbq that also does sushi and has a lunch buffet. Generally quite good. There's another Korean place in the same shopping center which I haven't tried, but which was recently recommended on chowhound.
The route 1 corridor is littered with Carribean places, none which have really stood out at me as being any more than decent, but I haven't tried all of them either.
South of IKEA in College Park:
On rt 1 south, on the left side just north of campus in the Campus Village Shopping center is the Food Factory II, and Afghan place. They make excellent naan in a tandoor and also bone-in chicken kebabs over a wood-fired grill. These are excellent. There are some other choices here at the lunchtime buffet, of varying quality. However you can get the kebab and the bread at the buffet, so it's a good deal to get that and try some of the other dishes to see if they are to your taste.
On eastbound Greenbelt road between rt 1 and Beltway plaza is Costa Alegre, a family-run Mexican restaurant. The tortas, sopas, and tacos are all good options here. I don't know if it's as good as the best places in Little Mexico Bladensburg, but it's definitely in the ballpark.
Second the Marathon rec.
Finally, if you're coming from Silver Spring per your location, there are tons of options along University Blvd on the way from SS to IKEA, including the obvious places such as Woodlands and Tiffin, Pho 75, and an infinite number of Central American trucks and holes-in-the-wall, which I probably couldn't cover if I spent the rest of my life trying (nonetheless, I will probably make the effort. It's important to have goals in life).