Considering that the nans you want to remove are the ones you put there on the previous lines, why put the nans in the first place?
To remove a row where any of the value on the row satisfy a condition, you would use the any function, so:
out_image(any(isnan(out_image), 2), :) = []; %remove rows that contain any nan
But as said, there's no point putting the nans there in the first place, so:
%replace the last three lines:
out_image = image_t(all(image_t > no_data, 2)); %only keeps rows of image_t whose values are ALL greater than no_data
Finally, note that the find is completely unnecessary in the code you wrote:
out_image(out_image <= no_data) = NaN;
%works exactly the same as
out_image(find(out_image <= no_data)) = NaN
