The electric semi-truck maker still faces existential challenges.Nikola's (NKLA -0.78%) stock has plunged nearly 99% over the past three years. The maker of electric semi-trucks was a red-hot stock during the buying frenzy in speculative stocks in 2020, but it ran out of juice after it missed its production forecasts.After that steep decline, Nikola's stock now trades at just 2 times this year's sales. Could this beaten-down EV stock unexpectedly roar back to life over the next three years? What happened to ...