Let’s look at important things here –
Mars - Mars represents our will power, courage, ability to take actions, aggressive nature, anger, our fighting ability, brother, male friends, a boy friend for a girl, a soldier, an athlete and real estate etc.
Krittika - It is nakshatra of criticism, cutting things, surgeries and bloodshed. Also, it is nakshatra of child care, secrecy, research, protection and foster parenting etc. It spreads from Aries to Taurus. It is ruled by Sun. For more info on Krittika, please check this link - https://www.astrosaxena.com/kritnaksh .
Aries – As Krittika is part of Aries, Aries sign and its representations become important here. Aries is the 1st sign of zodiac belt, so it represents the things and energy of 1st house of horoscope like Self, Personality etc. Besides that, Aries is the sign of our individuality, our aggression, our actions, our competitive ability etc. Aries is ruled by Mars and it is consisted of 2 and half Nakshatras named Ashwini, Bharani and Krittika.
Taurus - As Krittika is also a part of Taurus, Taurus sign and its representations become important here. Taurus is the 2nd sign of zodiac belt, so it represents many things related with 2nd house of horoscope like, Hoarded Wealth, Assets, Savings, Finances, Luxuries and Liquid Money. All in all a sign related with luxuries and all the conveniences of life. Taurus is consisted of 2 and half Nakshatras, i.e. Krittika, Rohini and Mrigshira. Taurus' lord is Venus.
Mars – As Mars rules Aries, Mars’ position and dignity is important to know about the overall functioning of any planet in Krittika/Aries.
Venus – As Venus rules Taurus, Venus’ position and dignity is important to know about the overall functioning of any planet in Krittika/Taurus.
Sun – Likewise as Sun rules Krittika, Sun's position and dignity is important to know about the overall functioning of any planet in Krittika.
Houses Involved – Also, we can’t afford to forget the houses involved as a planet can be ruling different houses and sitting in different house for every person as per ascendant and planet’s position. To know overall affect, we have to consider the houses involved as those areas of life are being impacted.
Interpretation of Mars in Krittika Nakshatra – Now, Mars is in Krittika Nakshatra which is very similar to Mars own nakshatra. As the story of Krittika nakshatra revolves around Kartikeya, the God of Wars, this placement can show a really aggressive person. In Aries portion, it can be even more aggressive as Mars is in own/mool trikona sign and Aries represents all the qualities of Mars. In Taurus section, we can say that aggression loses its direction as Mars is no more in its fiery element. Mars in Krittika can easily show someone in Police, Army or any kind of defense services. It can also get someone into medical side of work especially Surgeon as a Surgeon does all those acts which are done by a Soldier, i.e. use of weapons and bloodshed. These people can be equally lethal with their speech and can wound many with their words. On positive terms, they can be very focused at their aim and will make any effort for the same. They can be damn protective towards their child. They can be very good at editing related work. They can be more driven towards wealth as a security measure in Taurus section of Krittika. Overall, it is a very strong nakshatra position of Mars and they just need to guide their aggressive nature and actions in positive direction.
Role of Mars – As we are trying to interpret Mars only, we need not to look for Mars's position and dignity separately as Aries's lord.
Role of Venus – Likewise, Venus's position will become important in functioning and results of Mars in Krittika/Taurus as Venus rules Taurus.
Role of Sun - As Sun rules Krittika, its position is also important to finally decide about the results of Mars in Krittika.
Other Factors – And of course, we need to consider conjunction, aspects, house lordship, house position and dashas etc to know the exact results of Mars in Krittika in either of the signs. So, we always need to take a holistic view of chart rather than just 1 planetary position.
Conclusion – So, this is how I see Mars in Krittika can work in a chart.
Hope this helps. Please post any comment or query you may have.