I have made this Rachel Ray "Mexican Lasagne" several times for my family as well as for a dinner exchange with some moms in my neighborhood. It is hearty and kid friendly. Not to spicey and you can alter the veggies in it that your family likes.
Go to the Food Network website. Type in Mexican Lasagne, select Rachel Rays. This also freezes well.
Also, I would recommend you consider doing a dinner exchange with some other moms you know. This is so great. This is how I have done it... Each mom cooks 4 meals of the same thing. Then, you keep one meal for your family and they you exchange the other 3 meals with the other mom's.So now you have 4 different meals, ready to go, you can freeze them, eat them, and even leftovers. This has really cut down on our food budgets, because we just by food for one recipe meal, not 4. You get a great variety, and it is a huge time saver during the week.
Hope this helps. Good luck with your growing family. How blessed your family is to have you willing to care for your nephew's.
L.