The Teesiders tasted victory in Suffolk for the first time since 1993 with an impressive second half showing, capped by goals from Christian Stuani and Nugent in a 2-0 win
The prolific striker netted for the 15th time in 14 games against Ipswich.
Karanka said: "It was an amazing win
We haven't won here since March 1993 and Ipswich were the better team in the first half when they were comfortable, played with more intensity and had the better chances
"If they had scored the first goal, we would have had a problem
But we played better in the second half and we controlled the game.
"It is good being at the top of the table
We are there because we are doing good things and we have an amazing squad, a better one than last season
But there is still a long way to go."
A closely-fought first half was characterised by half chances at either end before Boro stepped it up after the restart and Ipswich failed to respond.
Middlesbrough should have broken the deadlock when Grant Leadbitter's close range shot was brilliantly blocked by Dean Gerken before they took the lead in the 54th minute.
Albert Adomah's deep cross was headed in by Stuani from close range, despite Gerken's best efforts.
The goal spurred Boro on and they proceeded to dominate the match.
The impressive Stewart Downing twice went close before he turned provider to make the points safe.
Downing's neat pass played in Nugent and he gained a yard on Tommy Smith to find the net via a deflection off the unfortunate Town defender and the inside of the post.
Ipswich were denied Dimi Konstantopoulos whose point blank save denied Jonas Knudsen.
Boro went even closer when Adomah saw his effort cleared off the line by Luke Chambers when it looked easier to score.
Ipswich manager Mick McCarthy said: "In the first half, I thought there were two good sides going at it.
"We shaded it slightly and I said at half-time it would be whoever blinked first or let their guard down.
"We didn't defend the far post for the first goal and when that goes in, it changes the game.
"They are a very good side and will be competing for a top two place at the end of the season.
"In Stewart Downing and David Nugent, they have two Premier League footballers probably on Premier League salaries
Nugent didn't have a kick before his goal but he took it well."
Source : PA
Source: PA