According to this List of Exoplanet Extremes:
The planets Kepler-70b and Kepler-70c approach each other to a distance of about 240,000 kilometers, and when they are at the closest approach, Kepler-70c would appear 5 times the size of the Moon in Kepler-70b's sky.
But from what I see they are unlikely to be habitable planets.
From what I have read the potentially habitable planet with the shortest year is TRAPPIST-1d with a year 4.05 Earth Days long.
TRAPPIST-1E at closest approach to TRAPPIST-1d would be about 2.731 times as far as the Moon is from Earth, and has 0.91 the radius of the Earth. The Moon has a radius of 0.273 the radius of Earth, so TRAPPIST-1E has 3.333 times the radius of the Moon. At it's closest approach TRAPPIST-1E would appear 1.220 times as wide as the Moon from TRAPPIST-1d, though at other times it would look much smaller than the Moon.
So this example shows that it is possible for a potentially habitable planet to sometimes get close enough to another planet in its solar system to see that other planet at least as large as the moon looks from Earth.
But if you want a situation where the other planet looks much larger than the moon from the surface of the habitable planet you will have to get someone else to construct your solar system and do the calculations.
Another possibility is a habitable planet in a Trojan orbit with a gas giant planet and a star. If the star is a really dim red dwarf the habitable planet would have to orbit very close to the star. Thus the orbit of the habitable planet would be a relatively small one and the 60 degrees of separation between the gas giant planet and the habitable planet would be a relatively small distance.
If the habitable planet and the gas giant planet orbit at 10,000,000 kilometers from the star, the two planets in a Trojan relationship would be about that far from each other. At that distance a gas giant the size of Jupiter would have an angular size of about 0.75 degrees or 45 arc seconds, about 1.5 times the angular diameter of the moon as seen from Earth.
The smaller, habitable planet would actually move a lot around the exact L4 or L5 position, and would get significantly farther and closer to the gas giant planet, making it appear sometimes smaller and sometimes larger than calculated.
Since TRAPPIST-1d is in the stellar habitable zone and orbits TRAPPIST-1 at only 3,330,000 kilometers, a habitable planet could be a third as far from its star as in the Trojan system above. Thus if the gas giant is as large as Jupiter it could appear 4.5 times as wide as the moon from the habitable planet in the Trojan position.
Unfortunately Jupiter is almost as large as the largest possible gas giant. Gas giant planets much more massive than Jupiter are believed to have smaller diameters as their intense gravity compresses their atmospheres.
Another possibility for a planet appearing very large as seen from a habitable planet would be a hot Jupiter. Hot Jupiters are gas giant planets orbiting very close to their stars and having very high temperatures, hundreds or thousands of degrees hotter than Earth. Some hot Jupiters are called "puffy planets" or "hot Saturns" because they are very large and have very low density. They are so hot that their atmospheres swell up and their diameters increase.
WASP-17b, the puffiest known planet, has about twice the diameter of Jupiter and half of it's mass.
Unfortunately, a habitable planet would have to orbit their star several times the distance of the hot Jupiter in order to have habitable temperatures. Thus their star would have to be a very dim one for their orbital separation to be only a few million kilometers. And the hot Jupiter would look the largest when it was between the habitable planet and the star and thus would look like a very thin crescent during the day.
Also you might want to check out this:
And ask about calculating to make the distances between planets as small as possible.
Thus my calculations indicate that it would be difficult to get another planet to appear more than a few times the apparent diameter of the Moon in the sky of a habitable planet. Possibly someone else can suggest a plausible orbital arrangement to make another planet look much larger.
But if the habitable world is not a planet but a hypothetical Earth-sized moon of a gas giant planet orbiting in the habitable zone of their star, the gas giant can appear quite large in the sky of the habitable moon. And other large moons would appear to get larger and smaller as they orbited the planet.
There are, of course, some limitations on the maximum and minimum apparent diameters of gas giant planets as seen from any habitable moons they may have.
If the planet has a diameter between those of Neptune and Jupiter, for example, the planet's apparent diameter as seen from a moon at a specified distance would be between those of Neptune and Jupiter at that distance. And depending on the mass of the planet and the mass and distance of the star, there are inner and outer limits for the orbit of habitable moons.
Can a gas giant have its own habitable zone?7