I don't think so, not just because the resulting size would be roughly 182x160, but because the hardware wouldn't allow it. The available background type that would allow it to be scaled in that manner is forced into a single 8-bit palette whereas the need for correctly drawing a background on the NES needs smaller, multiple palettes.
If there was a software-based emulator, that could do it, but all the NES emulators on the GBA use the GBA's 2D hardware to recreate the NES's native drawing functions, which is the reason games run at full speed. This hardware emulation means that while you can scale things vertically, you cannot scale horizontally, and that's just due to the quirks of the GBA's 2D hardware which you would need to know more about coding to truly understand, so just take my word on that for now.
Check out the very bottom paragraph of http://pocketnes.org/res.html and the page it links to and you'll see that even if you could do it, you really wouldn't want to.
The version of NES DS that uses software emulation might be able to scale proportionately, but I do not know this for a fact.
I would like to mention that NES games were designed to be played on 4:3 televisions. The actual NES resolution is not 4:3, but the way most games graphics are done so that it looks normal when stretched to 4:3 (for example, on Kirby's Adventure, the intro graphic of Kirby looks stretched vertically kind of like on oval when played on a NES emulator with unaltered resolution, but when played on a standard TV, it looks like a circle. The actual graphic data has a more oval-shape, simply because NES resolution is not 4:3, but TV's are 4:3 so it stretches the NES screen horizontally)
impossible for a correct aspect ratio. 240x160 is a better choice and possible PocketNES does NOT support sprites scaling and mid-frame chr table switches for sprites(both of them are supported by nesDS), which make some games look bad.
Just pray that Dwedit will update it.