Not even close. Tegus need 8x4 caging just like a lot of monitors. Pretty much any large lizard(monitor, tegu, iguana) is going to need 8x4. Iguanas need the height and monitors need a few feet of deep dirt to dig in. Its the main reason i had to rehome my 5' Nile Monitor. At the time i was young and didnt have the cash to afford to build him a 10x6x6 cage.
Not to sound like a jerk but you shouldn't try and find a reptile to go around your cage. You should find a reptile you like and then order/build a cage around them. Trying to ask 'can i keep X in X size tank/cage' sounds like so many stories i've heard of 'my reptile grew too big for his cage and i couldnt afford the right one for him'. I'm guilty myself with my Nile Monitor but i was a teenager and bought a hatchling off a breeder i knew. Luckily, the breeder found him a good home with a guy who had lots of monitors and converted a couple rooms in his house into full size caging so he got set up nicely.