When I bought my horse Red a year and a half ago, he was a same way. Very pushy and in-your-face.
Key points --> YOU NEED TO BE CONSISTENT WITH HIM. Always, always, always correct him when he gets in your space. Never let him get away with it. And practice, practice, practice handling him on the ground. I really am a big fan of Clinton Anderson because he does lots of ground work and explains what he is doing and why.
You should be able to easily control all parts of your horse's body from the ground: hindquarters, ribcage, shoulders, head. When I was teaching this to my horse, it found it very useful to use a whip, simply because it creates an extension of your arm. Very useful for disengaging those hindquarters! Eventually, you should be able to "glare" at his hindquarters, and he should move them away from you. Same with shoulders.
Plan to spend 10 to 15 minutes every single day working on groundwork, if you want your horse to respect your space. You should be able to move his feet in any way you want, by your body language. You can also work on getting him to back up simply from the jiggle of the leadrope and you "glaring" at his chest.
Also make sure that he drops his head when you ask, and leads willingly at the walk andn trot wherever you take him.
CONSISTENCY and PRACTICE will give your horse good ground manners.
As far as the treats comment goes ..... I don't buy that. My horses get hand-fed treats all the time. But they don't bite. And they don't get into my space uninvited. Because I've taught them to respect me. I just like to give them treats to spoil them.