What are my options with a GATE 2019 score of 747 in the PI (Production & Industrial Engineering) paper? Is NITIE or top IITs possible?

As per your score and previous year cutoff, the colleges you get in first round are:-

IIT Kanpur Industrial and Management Engineering Industrial and Management Engineering

IIT Indore Mechanical Engineering Production and Industrial Engineering

IIT Delhi Applied Mechanics Engineering Analysis and Design

IIT Kanpur Material Science and Engineering Material Science and Engineering

Motilal Nehru National Institute of Technology Allahabad Department of Mechanical Engineering Production Engineering

Motilal Nehru National Institute of Technology Allahabad Department of Mechanical Engineering Product Design and Development

Malaviya National Institute of Technology Jaipur Department of Mechanical Engineering Production Engineering

Malaviya National Institute of Technology Jaipur Department of Mechanical Engineering Production Engineering

National Institute of Technology Kurukshetra Department of Mechanical Engineering Industrial & Production Engineering

Indian Institute of Engineering Science and Technology Shibpur District Howrah Department of Mechanical Engineering Production Engineering

To know more about your chances of getting other colleges check out the PSU/college predictor link below:

https://engineering.careers360.com/gate-college-predictor