The chief judicial magistrate sent her to judicial custody and asked the jail authorities to conduct a health checkup on her as she was claiming to be unwell and submit a report to the court on April 17.
The court will announce further steps after going through the report.
Nath, who had been in police custody for a day, was arrested on Tuesday from MLA Hostel here in connection with her alleged links with the racket whose kingpin Anil Chauhan was nabbed earlier this month.
The MLA from Barkhola in Cachar district was arrested under IPC Sections 120B (criminal conspiracy), 212 (harbouring offender), 420 (cheating) and 468 (forgery).
The Gauhati High Court had rejected two interim anticipatory bail applications of Nath in connection with a case registered at Dispur police station and another at Azara police station.
She filed the anticipatory bail pleas on April 9 after the arrest of her estranged second husband Jacky Zakir.
Zakir was arrested on April 8 from his house in Badarpur in Karimganj district, while Nath's Personal Security Officer Bedabrata Barpatra Gohain was also arrested from the Special Branch headquarters here on the same day.
During investigations, it was found that Chauhan was issued Assam Assembly car passes on Nath's recommendation.
Following this, the Assembly Secretariat asked her to explain why she made the recommendation. Nath replied that she signed the car pass application form of Chauhan's wife Rita who is a Congress worker.
According to police, one of the luxury cars used by Zakir was suspected to be a stolen one and sold by Chauhan to the MLA, who allegedly 'gifted' it to Zakir.
Assam Congress President Anjan Dutta too issued a show cause notice her for alleged involvement with Chauhan.
The controversial MLA had married Zakir in 2012 by converting to Islam and without divorcing her first husband.
The couple, who were assaulted by a mob at a Karimganj hotel in July 2012, parted ways last year and are living separately since then.