For all of its Nintendo customizations, the Switch is ultimately a tablet running a garden variety NVIDIA Tegra processor -- and that means it can potentially handle the same software as other mobile devices. To prove that point, the fail0verflow team has shown a Switch running an honest-to-goodness Linux distribution. The touchscreen, networking and accelerated 3D graphics are all functioning, as evidenced by the modders tweeting from the Switch and running a benchmark. You're not about to run Steam games on it (many Linux apps aren't built for ARM-based chips), but you could theoretically use the Switch as a basic computer.
Fail0verflow hasn't explained exactly how the necessary exploit works, but it may be easier than you think. The team previously noted that it's taking advantage of a bug in the Switch's bootrom (the fixed low-level code that runs the moment you turn the device on), which prevents Nintendo from patching it on current consoles. You don't need a mod chip, either. The only way for Nintendo to thwart this is to release updated hardware, and that might not happen for a while.
There's no word yet on whether or not the exploit and techniques involved will be made widely accessible. Don't expect to try this at home, then, even if you're willing to throw caution (and your warranty) to the wind. As it stands, this is more of a because-we-can hack than something many Switch owners would find practical. You'd probably get better value out of running homebrew games, and that's a tougher challenge given that Nintendo can easily update its operating system to block unauthorized software.