Ms Truss joined audience members representing a cross-section of political opinion in the Red Wall Greater Manchester town of Leigh.
She answered questions on Brexit, housing, employment and migration as GB News viewers quizzed the Foreign Secretary on her leadership credentials.
But Nigel was not impressed with her position on immigration.
In the live event, refereed by GB News' Alastair Stewart, Ms Truss joked about how uncooperative the French are being about stopping small boat crossings.
Nigel Farage responding to Liz Truss' performance in the People's Forum
GB News
Nigel Farage speaking to Michelle Dewberry after the People's Forum
GB News
Nigel suggested this was non-commital, though.
He claimed she "had nothing to say about pushback" and warned "Prime Minister Liz Truss will just see tens of thousands more people crossing the Channel".
He added that she "seemed very proud" of the Rwanda policy, noting that her appearance was "very, very disappointing" as she "didn't take" the opportunity of breaking away from Rishi Sunak in the Conservative Party leadership race.
On housing, GB News viewer Jessica said she is concerned she will "never become a homeowner" and asked what plans are in place to address this.
Ms Truss said she wants "more young people to get on the property ladder" and proposed a policy whereby rental history contributes to the mortgage application process.
On the NHS, she said "there is a question as to how we could encourage" some of those people who have "left the NHS to come back and help out".
Explaining why she had accepted an invitation from GB News to appear in the People's Forum, Ms Truss said: "I am looking forward to talking to GB News viewers and our members in the heart of our Red Wall and taking their questions.
"As Prime Minister, I will work tirelessly to deliver for those who voted for us across the Red Wall, including those who put their trust in us for the first time in 2019.
"I have a bold and ambitious economic plan and the experience in Government to deliver it.
"I am on the side of people who work hard and do the right thing and as Prime Minister I will make sure we are an ‘aspiration nation’ with a fast-growing economy and ensure every part of the country thrives.”
