Unless the political situation between China and the US improves dramatically, NIO just can't be a "Tesla killer" without tariff free access to the American market, the largest car market in the world.
With the current Biden administration promising to protect American manufacturing and the promise to promote the sale of EV in America, the President finds himself with a problem for which there is only 2 solutions:
Helping American manufacturers
Apart from Tesla who already has a complete EV offer, from SUV to sedan, cross-over, compact sedan, roadster and the upcoming Cybertruck, none of the other manufacturers can make such claims. Tesla can also claim another title of becoming a battery manufacturer on top of possibly mining its own lithium... Vertical integration in battery manufacturing "from the mine to the car" could make help Tesla dominate the market for years to come.
Ford may have produced an electric Focus (not counting hybrids) but it's only "real" offer on the EV market is the Mustang Mach-E, waiting for the still in development electric F-150.
GM has a good offer with the, somewhat bland, Bolt EV, it's Hummer will not reach mass production for a while (only a few thousands produced in the first run). GM's ace in the hole is its Ultium platform which will help it not only bring the Lyriq and other models to market but will also turn GM into a supplier to other manufacturers.
Stellantis (Chrysler) has several plants in America, although its EV offer mainly concerns its European brands such as Peugeot and Citroen. Will those brands come to America?
Rivian, Lordstown, Lucid are still unknown values, will they be able to reach mass production without going through "production hell"? Will the quality of the mass produced cars match that of the prototypes? Will they be constrained by battery availability? How many cars will they produce on a yearly basis?
Convince Chinese and European EV manufacturers to produce EV in America
Now this is the likeliest possibility to achieve rapid electrification of the American car market. With crafty policies and reasonable incentives, the Biden Administration can convince the main Chinese players, XPeng and NIO to invest in manufacturing some of its cars in America, much like Honda and Toyota have been doing for decades.
The only awkward proposition is that the Chinese Communist government owns interests in most Chinese EV manufacturer either directly in shares or through its state-owned banks, meaning that their American employees would be working (in part) for the Chinese government. I can see a possibility where the CCP would have to give up its shares in those companies in exchange for entry on the American market.
Volkswagen will soon start production of the ID.4 in Chattanooga, Tennessee but will not offer the ID.3 in America. Other VW models that should appear on the market as soon as 2024 could also be produced in America.
Nissan also already produces the Leaf in America, with other EV models coming, we could see the expansion of its EV manufacturing in the US as a very likely scenario.
BMW also has a plant in Greer, South Carolina which could be tooled to mass produce EV and so does Mercedes.
Other manufacturers. Kia, Hyundai, Honda and Volvo (Polestar) who already produce EV do not yet make those models in America. A push by the Biden administration could change that as those manufacturers already operate large car plants in the country.
So, unless NIO manages to enter the American market and that will require the Biden administration to reach a deal with the Chinese government, it just cannot be a "Tesla Killer".