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."
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."