Oct 21 (Reuters) - Shares of Portillo's Inc rose 30% in their Nasdaq debut on Thursday, valuing the restaurant chain known for its Chicago-style hot dogs at $1.9 billion.

The company's shares opened at $26. Portillo's sold 20.3 million shares in the offering priced at $20 apiece, the upper end of its price range, raising a little over $405 million.

Portillo's move to go public was also a sign that the U.S. IPO market has not lost steam and its market debut comes as restaurant chains benefit from a return to dining out brought by vaccine rollouts and easing COVID-19 curbs.

Portillo's, which is backed by private equity firm Berkshire Partners, traces its roots back to 1963, when Dick Portillo invested $1,100 into a small trailer to open the first Portillo's hot dog stand in Villa Park, Illinois, which he called "The Dog House."

The company, which was renamed Portillo's in 1967, has now grown across nine states in the United States to 67 restaurants, most of which feature double lane drive-thrus and also include dine-in, carryout and curbside access.

Portillo's menu features all-American staples such as Chicago-style hot dogs and sausages, Italian beef sandwiches, chopped salads, burgers, crinkle-cut french fries, homemade chocolate cake and milkshakes.

The company expects third-quarter revenue of $138 million, an over 15% jump from a year ago, according to its IPO filing.

Each Portillo's location, on average, served about 825,000 guests in the twelve months ended June 27.

Jefferies, Morgan Stanley, BofA Securities and Piper Sandler are among the underwriters for the offering. (Reporting by Noor Zainab Hussain in Bengaluru; Editing by Shailesh Kuber)