The brand claims that the three designers - Mark Miner, Marc Dolce and Denis Dekovic - "stole" product concepts and marketing plans that will benefit its biggest competitor.
The three designers, who were senior figures in Nike's footwear, football and basketball design studios, left the Oregon-based brand earlier this year to start their own studio.
In September the trio announced they would begin working for Adidas in 2015, heading up the new Adidas Creative Studio in Brooklyn, once their non-competition agreement with Nike had expired.
The announcement followed a battle between the two brands for dominance during the FIFA World Cup in Brazil. Official tournament sponsor Adidas launched its Battlepack boot collection and a popular new football, fighting off guerrilla marketing tactics from Nike, who commissioned typographers Wim Crouwel and Neville Brody to help redesign team kits.
Now Nike has launched a legal attack against its three former designers, with a lawsuit containing eight complaints – including breach of duty, breach of duty of loyalty and misappropriation of trade secrets – in Multnomah County Circuit Court in Oregon.
A copy of the suit published by local paper Portland Business Journal on Scribd, alleges that the three designers "conspired to and developed for themselves, and then for Adidas, a strategic blueprint for a creative design studio to compete against Nike, began consulting with Adidas (and) misappropriated Nike trade secrets for use in their new business venture and attempted to destroy evidence of their scheme."
Nike said the "plot" had "sprung to life" in April 2014, when it alleges the designers began "a campaign to promote their independent design studio venture" by buying social media followers to create "false perception of buzz and popularity surrounding their design careers."
Dolce was formerly Nike's global basketball and training design director, Dekovich was global football design director and Miner was senior global footwear designer.
Nike claims that they promised to bring information to Adidas that would hurt Nike, including its strategic plans for the next two to three years in running, sportswear and football.
It also claims that the designers began working for Adidas while still Nike employees, "in direct and flagrant violation of their noncompete agreements".
The legal document listed the material it claims the designers "stole", including "future strategic development plans, product offering and product launches", "unreleased product technology", "virtual testing methodologies" and "marketing campaign materials", and demands both a jury trial and $10 million (£6.4 million) compensation.
"We believe the complaint Nike filed against former footwear employees Denis Dekovic, Marc Dolce and Mark Miner explains the situation clearly," a Nike spokesperson told Dezeen. "Nike is an innovation company and we will continue to vigorously protect our intellectual property."
The designers defended themselves against the allegations in a statement posted by Dekovic on Twitter.
— dD (@DenisDekovic) December 9, 2014
"We find Nike's allegations hurtful because they are either false or are misleading half-truths," it said. "We did not take trade secrets or intellectual property when we departed Nike in September."
"During our entire careers at Nike, we gave nothing but our maximum effort. We collectively poured in hours, passion and dedication beyond what was asked or expected of us, often prioritising our jobs over our families."
"Until the very end, we stayed engaged, loyal and committed. We have a tremendous amount of respect for our colleagues and Nike and would never do anything to harm them."
Despite being based in Germany, Adidas had agreed to open a new studio with the designers in Brooklyn to serve as its first "open-source creative centre".
"The Brooklyn Creative Studio will be a small but essential operation aimed at exploring design direction for the brand," said Paul Gaudio, Adidas global creative director. "This facility will be an open-source creative centre allowing us to connect and collaborate with consumers in a way we've never done before."
"What these three will bring alongside their design talent is almost more valuable to Adidas; their high level of marketing and product execution experience (think Primeknit vs Flyknit), they also bring some of Nike's "cool factor" to Adidas through their previous association with the brand," he wrote.