I just used Nano Banana Pro from LMArena, but if you have access to a paid account I'd love to see you try it out! I just gave it the puzzle image as an input along with the prompt: "Please solve this word search puzzle".

For generating the prompt which included the word positions I had Gemini 3 Pro do that using the following prompt: "Please try to solve this word search puzzle. Give me the position of each word in the grid. Then generate a prompt which I can pass to Nano Banana Pro, which I will pass along with the same input image to see if Nano Banana Pro is able to properly highlight all the words if given their correct position."