Will Anderson, another Scrabble champion/grandmaster, uploaded a video talking about Nigel's win here. The win is a lot more impressive than memorizing bingoes - Spanish scrabble has different letter distributions and point values, resulting in different metas. He didn't just memorize the Spanish Scrabble dictionary - he learned how to play Spanish Scrabble and dominated the first Spanish tournament he participated in.

Definitely worth a watch if you're interested in Scrabble at all: https://www.youtube.com/watch?v=6RvNxkQ6Bgs