The Japanese car-making giant unveiled a £52m new production line at the factory in Sunderland on Friday as it ramps up preparations for the next-generation Qashqai sports utility vehicle.
The company has previously warned its European business would be unsustainable if the UK’s departure from the EU lead to tariffs.
Manufacturers fear any additional customs checks, tariffs and regulations could add costs, slow down production processes and potentially grind output to a halt.
The UK is negotiating a free trade deal with the EU, but could leave the bloc at the end of the transition period without an agreement if negotiations fail.
Nissan’s commitment to continue investing in the Sunderland plant – the largest car factory in the UK – is a boost to the country’s struggling automotive industry, which has slumped to its lowest output for a decade.
The company currently builds its Leaf, Qashqai and Juke models in Britain, but it axed premium Infiniti vehicles last year, cutting output, and has been hit by a slump in diesel demand.
Unite national officer Steve Bush said: “The reaffirmation of this already announced investment of £400m in a new production press at the Sunderland plant is a welcome confidence booster for the 6,000-strong workforce.
“In challenging economic times, such investment by Nissan is warmly welcomed and a big vote of confidence in the world class, highly skilled workforce that has an excellent record in producing world-class cars.”
Ashwani Gupta, Nissan’s chief operating officer, said the Sunderland factory “continues to set the standard for productivity and quality”.
A production press weighing more than 2,000 tonnes has taken 18 months to install at the plant, and the first specially commissioned panels were made on the machinery on Friday.